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Sample records for exciting rxte science

  1. Recent Results from RXTE

    NASA Astrophysics Data System (ADS)

    Swank, J.

    1998-05-01

    The Rossi X-ray Timing Explorer has observed a wide range of sources and is producing valuable science. Its broad-band sensitivity has been key in the observations of both compact, stellar, and nebular objects. RXTE is ideally suited for observing X-rays from both galactic and extragalactic black holes. The range of accretion rates, masses, and possibly angular momenta of stellar black hole candidates produce a variety of phenomena on which there are new results. Cygnus X-1 has temporal as well as spectral properties, sensitive to state transformations, which strongly constrain the physical picture for a whole class of sources. Quasi-periodic oscillations are characteristic of the microquasar GRS1915+105 and some are seen in other candidates. Coordinated observations have established the link betweeen accretion instabilities and emission in jets. Accretion onto the massive black holes in AGN also results in variations. These have inspired many observations of correlations with both gamma rays and long wavelengths. Most neutron star X-ray sources are in low-mass binaries where relatively low magnetic fields allow accretion disks to persist where gravity is strong. With its high time resolution and large area RXTE is the only mission that can explore the domain of millisecond oscillations. Its measurements are providing evidence about the conditions at the neutron stars and determining spins, masses, and radii. In strong field accreting pulsars, quasi-periodic modulations may be diagnostic of the disk-magnetosphere interaction and the enigmatic spin behavior of some pulsars. RXTE recently discovered the fastest young rotation-powered pulsar. Among the special objects RXTE had the opportunity to observe are the bursting pulsar and the soft-gamma-ray repeater SGR1806-20. RXTE's fast response was recently applied to the transient XTE J0421+56, which had an exceptionally fast rise and decay. This led to identification of corresponding radio and optical transients of the symbiotic star CI Cam.

  2. Communicating the Excitement of Science

    SciTech Connect

    Michael Turner

    2009-06-05

    In this talk (which will include some exciting science) I will discuss some lessons I have learned about communicating science to scientists (in my own field and others), students, the public, the press, and policy makers in giving 500+ colloquia and seminars, 300+ public lectures and many informal presentations (including cocktail parties).

  3. Communicating the Excitement of Science

    ScienceCinema

    Michael Turner

    2010-01-08

    In this talk (which will include some exciting science) I will discuss some lessons I have learned about communicating science to scientists (in my own field and others), students, the public, the press, and policy makers in giving 500+ colloquia and seminars, 300+ public lectures and many informal presentations (including cocktail parties).

  4. RXTE Observations of Cas A

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.; Lingenfelter, R. E.; Heindl, W. A.; Blanco, P. R.; Pelling, M. R.; Gruber, D. E.; Allen, G. E.; Jahoda, K.; Swank, J. H.; Woosley, S. E.; Nomoto, K.; Higdon, J. C.; Dermer, Charles D. (Editor); Strickman, Mark S. (Editor); Kurfess, James D. (Editor)

    1997-01-01

    The exciting detection by the COMPTEL instrument of the 1157 keV Ti-44 line from the supernova remnant Cas A sets important new constraints on supernova dynamics and nucleosynthesis. The Ti-44 decay also produces x-ray lines at 68 and 78 keV, whose flux should be essentially the same as that of the gamma ray line. The revised COMPTEL flux of 4 x l0(exp -5) cm(exp -2)s(exp -1) is very near the sensitivity limit for line detection by the HEXTE instrument on RXTE. We report on the results from two RXTE observations - 20 ks during In Orbit Checkout in January 1996 and 200 ks in April 1996. We also find a strong continuum emission suggesting cosmic ray electron acceleration in the remnant.

  5. RXTE observations of AGN

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.; Heindl, W. A.; Blanco, P. R.; Gruber, D. E.; Marsden, D. C.; Pelling, M. R.; Jahoda, K.; Madejski, G.; Swank, J. H.; Zdziarski, A. A.; Gierlinski, M.; Hink, P. L.

    1997-01-01

    The Rossi X-ray Timing Explorer (RXTE) observed three active galaxies during its in-orbit verification phase: NGC 4151; NGC 4945, and MCG 8-11-11. All three were detected from 2 keV to more than 100 keV by a combination of the proportional counter array (PCA) and the high energy X-ray timing experiment (HEXTE). The PCA contains five, xenon/methane, multilayer, multiwire, gas proportional counters covering the 2 to 60 keV range, while HEXTE is an array of eight NaI/CsI phoswich scintillation counters covering the 15 to 250 keV range. The three active galaxies represent the classes of Seyfert 1, Seyfert 2 and intermediate Seyfert galaxies. The results of the fitting of various models containing partial covering fractions, Compton reflection components and high energy spectral breaks are discussed.

  6. RXTE Observations of Selected Blazars

    NASA Technical Reports Server (NTRS)

    Aller, Margo F.

    2002-01-01

    The work completed includes the analysis of observations obtained during Cycles 4 and 5 of the Rossi X-ray Timing Explorer (RXTE). The project is part of a longer-term, continuing program to study the X-ray emission process in blazars in cooperation with Dr. Ian McHardy (U. of Southampton, UK). The goals of the program are to study the X-ray emission mechanism in blazars and the relation of the X-ray emission to changes in the relativistic jet. The program includes contemporaneous brightness and linear polarization monitoring at radio and optical wavelengths, total and polarized intensity imaging at 43 GHz with a resolution of 0.1 milliarcseconds with the Very Long Baseline Array (VLBA), and well-sampled X-ray light curves obtained from a series of approved RXTE programs.

  7. The RXTE Education/Public Outreach Program

    NASA Astrophysics Data System (ADS)

    Lochner, J. C.

    The RXTE E/PO program was initiated during the summer of 1995 with our first summer teacher intern. The RXTE Learning Center went on-line shortly after launch, and since then has continued to provide information, results, and data from RXTE to the general public and the education community. Along the way, we've written an activity booklet (which includes a color paper model of the satellite), put the ASM data on-line for teachers and students to use, developed lesson plans and activities for those data, and involved students in the Shenandoah Valley in an RXTE observation.

  8. INTEGRAL and RXTE Observations of Centaurus A

    SciTech Connect

    Rothschild, Richard E.; Wilms, Joern; Tomsick, John; Staubert, Ruediger; Benlloch, Sara; Collmar, Werner Madejski, Grzegorz; Deluit, Sandrine; Khandrika, Harish; /La Jolla High School

    2006-01-17

    INTEGRAL and RXTE performed three simultaneous observations of the nearby radio galaxy Centaurus A in 2003 March, 2004 January, and 2004 February with the goals of investigating the geometry and emission processes via the spectral/temporal variability of the X-ray/low energy gamma ray flux, and intercalibration of the INTEGRAL instruments with respect to those on RXTE. Cen A was detected by both sets of instruments from 3-240 keV. When combined with earlier archival RXTE results, we find the power law continuum flux and the line-of-sight column depth varied independently by 60% between 2000 January and 2003 March. Including the three archival RXTE observations, the iron line flux was essentially unchanging, and from this we conclude that the iron line emitting material is distant from the site of the continuum emission, and that the origin of the iron line flux is still an open question. Taking X-ray spectral measurements from satellite missions since 1970 into account, we discover a variability in the column depth between 1.0 x 10{sup 23} cm{sup -2} and 1.5 x 10{sup 23} cm{sup -2} separated by approximately 20 years, and suggest that variations in the edge of a warped accretion disk viewed nearly edge-on might be the cause. The INTEGRAL OSA 4.2 calibration of JEM-X, ISGRI, and SPI yields power law indices consistent with the RXTE PCA and HEXTE values, but the indices derived from ISGRI alone are about 0.2 greater. Significant systematics are the limiting factor for INTEGRAL spectral parameter determination.

  9. RXTE Observation of the TYCHO Supernova Remnant

    NASA Astrophysics Data System (ADS)

    The, Lih-Sin

    1998-01-01

    SN1006 [4] and Cas A [1, 9] supernova remnants have been shown convincingly to have a hard X-ray power-law continuum. This continuum is thought to be the synchrotron radiation from accelerated electrons of approx. 100 TeV at the shock fronts. Our goal of AO2 RXTE observation is to detect the hard X-ray continuum and to determine the nature of the continuum from Tycho SNR. A detection of a power-law continuum from Tycho SNR can strongly argue for SNRs are the source of cosmic rays with the first order Fermi acceleration as the energizing process. We report the results of our AO2 RXTE 1 x 105 sec observation of Tycho SNR. We detect two components of the X-ray spectrum from Tycho SNR both at better than 3 omega confidence. The best two component models are: bremsstrahlung (kT=2.67 +/- 0.13 keV) + bremsstrahlung (kT=7.07 +/- 2.21/1.72 keV) or bremsstrahlung (kT=2.36 +/- 0.21/0.57 keV) + power-law (gamma=2.58 +/- 0.12/0.09 ). This result is an improvement compaxed with the previous most sensitive X-ray measurements by Ginga which shows Tycho's observed X-ray continuum requires a two-component model to yield acceptable fits with the hard component parameters being highly uncertain. Our RXTE measurements constrain all parameter within 3o, ranges. However, we cannot yet distinguish between thermal and nonthermal models for the hard component. In the followings, we describe what we accomplished in the period covered by the grant proposal.

  10. RXTE Observations of Persistent Galactic Microquasars

    NASA Astrophysics Data System (ADS)

    Smith, David M.

    1997-04-01

    We are studying two persistent black hole candidates in the Galactic bulge, 1E 1740.7-2942 and GRS 1758-258, with the Rossi X-ray Timing Explorer (RXTE). These two objects have received particular attention because, like some black-hole x-ray transients, they have radio jets which suggest a resemblance to active galactic nuclei. They are also among the leading candidates for sources of the Galactic Center positrons. Strong optical extinction has so far prevented the identification of optical counterparts, so the nature of the systems must be deduced by comparison with other systems. With RXTE, we now have measurements of fast variability in these objects for the first time. I will present these timing results and our spectral results, and compare them with other black hole systems such as Cyg X-1 and with the low-magnetic-field accreting neutron stars (``atoll sources''), which are easiest to confuse with black holes when using high-energy observations alone.

  11. X-Ray Pulsar Studies With RXTE

    NASA Technical Reports Server (NTRS)

    Rappaport, Saul

    2004-01-01

    Our activities here at MIT have largely concentrated on four different binary X-ray pulsars: LMC X-4; 4UO352+3O/XPer; 4U0115+63; and X1908+075. We have also recently initiated a search for millisecond X-ray pulsations in RXTE archival data for several bright LMXBs using a new technique. Since this study is just getting under way, we will not report any results here. Using RXTE timing observations of LMC X-4 we have definitively measured, for the first time, the orbital decay of this high-mass X-ray binary. The e-folding decay time scale is very close to lo6 years, comparable to, but somewhat longer than, the corresponding orbital decay times for SMC X-1 and Cen X-3. We find that the orbital decay in LMC X-4 is likely driven by tidal interactions, where the asynchronism between the orbital motion and the rotation of the companion star is maintained by the evolutionary expansion of the companion. Under NASA grant NAGS7479 we carried out RXTE observations of X Per/4U0352+30 in order to track the pulse phase over a one year interval. This effort was successful in tentatively identifying a N 250-day orbital period. However, due to the fact that the observing interval was only somewhat longer than the orbital period, we asked for the observations of X Per to continue as public, or non-proprietary observations. Dr. Jean Swank kindly agreed to the continuation of the observations and they were carried out on a less frequent basis over the next year and a half. After 72 separate observations of X Per, we have the orbital period and semimajor axis firmly determined. In addition, we were able to measure the orbital eccentricity-which turns out to be remarkably small (e = 0.10) for such a wide binary orbit. This has led us establish the birth of a neutron star with a very small (or zero) natal kick.

  12. RXTE Observations of Several Strong Flares from the TeV Blazar 1ES 1959+650

    NASA Technical Reports Server (NTRS)

    Krawczynski, Henric

    2004-01-01

    Responding to the RXTE Cycle 7 NASA Research Announcement, we proposed to use the RXTE X-ray telescopes to intensively observe the TeV Gamma-ray Blazars Markarian 421, Markarian 501, 1ES 1959+650 and 1ES 1426+428, when their X-ray or TeV Gamma-ray fluxes would surpass preset trigger thresholds. In May and June, 2002, the Blazar 1ES 1959+650 (z=0.048) showed a series of spectacular X-ray and gamma-ray flares. Following the detection of a strong Gamma-ray flare on May 16 and 17 with the VERITAS 10 m Cherenkov Telescope, we invoked intensive RXTE observations, as well as complementary radio, optical and GeV/TeV Gamma-ray observations. From May 18 to August 14, more than 150 ksec RXTE observations were taken, yielding a unique data set with simultaneous RXTE and GeV/TeV Gamma-ray coverage.We used the financial support from the ADP program of NASA s Office for Space Science to perform a comprehensive analysis of the RXTE data. We studied in detail the temporal and spectral characteristics of the source. We collected multiwavelength data from a large number of collaborators, and performed a detailed cross-correlation analysis. Eventually, we interpreted the results in the framework of a Synchrotron-Self Compton model. The most important discovery of our research has been the detection of an orphan gamma-ray flare , not associated with an X-ray flare. The discovery showed conclusively that most models invoked to describe the non-thermal emission from blazars are overly simplistic.

  13. RXTE Observations of Magnetic Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Rana, V. R.; Singh, K. P.

    2003-03-01

    Results from hard X-ray observations with RXTE of 5 Polar systems-V2301 Oph, V1432 Aql, EP Dra, GG Leo and V834 Cen, and an Intermediate Polar TV Col are presented. An improved ephemeris for V2301 Oph using mid-eclipse timings has been derived. V1432 Aql shows structured lightcurve containing several prominent peaks and dips. A likely eclipse of X-ray source in EP Dra is observed for the first time. The X-ray emission in EP Dra and GG Leo is found to be consistent with a single pole accretion. V 834 Cen was observed to be bright during 1996-1998, but was 16 times fainter during 2002 observations. The power spectrum of TV Col shows a significant power at frequencies corresponding to the spin period (1910s) and the binary period (5.5hr) and their side-bands, thereby suggesting that both the stream-fed and disk-fed accretion components are present in TV Col.

  14. More Science Activities. 20 Exciting Experiments To Do!

    ERIC Educational Resources Information Center

    Smithsonian Institution, Washington, DC.

    Science and technology affect every facet of human life. By the 21st century, society will demand that all of its citizens possess basic competencies in the fundamentals of science and the use of technology. As science increasingly becomes the dominant subject of the work place, it is important to begin developing within children an understanding…

  15. Still More Science Activities. 20 Exciting Activities To Do!

    ERIC Educational Resources Information Center

    Smithsonian Institution, Washington, DC.

    Science and technology affect every facet of human life. By the 21st century, society will demand that all of its citizens possess basic competencies in the fundamentals of science and the use of technology. As science increasingly becomes the dominant subject of the work place, it is important to begin developing within children an understanding

  16. Low-mass X-ray Binaries with RXTE

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Below are the publications which directly and indirectly evolved from this very successful program: 1) 'Search for millisecond periodicities in type I X-ray bursts of the Rapid Burster'; 2) 'High-Frequency QPOs in the 2000 Outburst of the Galactic Microquasar XTE J1550-564'; 3) 'Chandra and RXTE Spectroscopy of Galactic Microquasar XTE 51550-564 in Outburst'; 4) 'GX 339-4: back to life'; 5) 'Evidence for black hole spin in GX 339-4: XMM-Newton EPIC-PN and RXTE spectroscopy of the very high state'.

  17. Using Space Science to Excite Hispanic Students in STEM

    NASA Astrophysics Data System (ADS)

    Reiff, P. H.; Galindo, C.; Garcia, J.; Morris, P. A.; Allen, J. S.

    2013-05-01

    Over the past ten years, NASA and its cosponsors have held an annual "NASA Space Science Day" at the University of Texas at Brownsville. The event is held over two days, with the Friday evening program featuring a space scientist or astronaut, this year Joe Acaba, giving a public lecture (plus a free planetarium show). The Saturday event starts with a keynote speech from the same speaker. Then the students circulate among six or seven hands-on workshops, plus a scheduled trip to the "Demo room" where NASA missions show their materials, and a planetarium show in the Discovery Dome. The students, 4th through 8th graders, are drawn from schools all across south Texas, and have included students coming as far as Zapata, with a four-hour bus ride each way. Over the ten years of the program, more than 5000 students have been reached. Most of the hands-on activities are led by undergraduate student mentors. The university students (42 in 2013) received science and engineering content and mentor training on the activities at Johnson Space Center before the January event. In addition, an additional 40 local high school students helped with activities and with escorting each group of students from one activity station to the next. The program has been so successful that students have "graduated" from participant, to volunteer, and now to University student mentor. Most of the mentors go on to complete a degree in a STEM discipline, and many have gone on to graduate school. Thus the mentors not only help with the program, they are beneficiaries as well. The program is being expanded to reach other underserved communities around the US, with its first "expansion" event held in Utah in 2011.; Puerto Rican Astronaut Joe Acaba and the Discovery Dome were two of the highlights for the students.

  18. "XMM/RXTE Observations of GX 339-4"

    NASA Technical Reports Server (NTRS)

    Nowak, M. A.; Corbel, S.; Fender, R.; Wilms, J.; Kuster, M.; Bailyn, C.; Coppi, P.

    2005-01-01

    In March 2003, we performed two simultaneous XMM/RXTE observations of the black hole candidate GX 339-4. Our goal is to compare these data to our prior simultaneous RXTE/ASCA observations (Nowak, Wilms & Dove, 2002). These observations were carried out in timing mode, as opposed to burst mode, and are more complex to analyze than we expected. Specifically, the data suffered from a number of telemetry dropouts (in fact, the standard archive processing failed on these data, and more than a year passed from the time of the observations before the data was delivered to us). Furthermore, the core of the EPIC PSF suffers slightly from pileup and gain shifts. We continue to work on this data, however, and anticipate publishing it within the next academic year. Here we highlight our ongoing work and outline our plans for publication.

  19. Discovery of QPO from X Persei with RXTE

    NASA Astrophysics Data System (ADS)

    Takeshima, T.

    The Rossi X-ray Timing Explorer (RXTE) satellite observed X Persei on March 19 and April 1, 1996. X Persei is the transient Be star binary X-ray pulsar with the pulse period of ~840 seconds. We report the results of the spectral and timing analyses in comparison with the results from ASCA observation in 1994. The periodical and aperiodical time variabilities, large spin-down rate, of soft energy emission component, and possibility of disk formation are discussed.

  20. RXTE Observations of LMC X-1 and LMC X-3

    NASA Technical Reports Server (NTRS)

    Wilms, J.; Nowak, M. A.; Dove, J. B.; Pottschmidt, K.; Heindl, W. A.; Begelman, M. C.; Staubert, R.

    1999-01-01

    Of all known persistent stellar-mass black hole candidates, only LMC X-1 and LMC X-3 consistently show spectra that are dominated by a soft, thermal component. We present results from long (170 ksec) Rossi X-ray Timing Explorer (RXTE) observations of LMC X-1 and LMC X-3 made in 1996 December. The spectra can be described by a multicolor disk blackbody plus an additional high-energy power-law. Even though the spectra are very soft (Gamma approximately 2.5), RXTE detected a significant signal from LMC X-3 up to energies of 50 keV, the hardest energy at which the object was ever detected. Focusing on LMC X-3 , we present results from the first year of an ongoing monitoring campaign with RXTE which started in 1997 January. We show that the appearance of the object changes considerably over its approximately 200 d long cycle. This variability can either be explained by periodic changes in the mass transfer rate or by a precessing accretion disk analogous to Her X-1.

  1. RXTE Observations of LMC X-1 and LMC X-3

    NASA Technical Reports Server (NTRS)

    Wilms, J.; Nowak, M. A.; Dove, J. B.; Pottschmidt, K.; Heindl, W. A.; Begelman, M. C.; Staubert, R.

    1998-01-01

    Of all known persistent stellar-mass black hole candidates, only LMC X-1 and LMC X-3 consistently show spectra that are dominated by a soft, thermal component. We present results from long (170 ksec) Rossi X-ray Timing Explorer (RXTE) observations of LMC X-1 and LMC X-3 made in 1996 December. The spectra can be described by a multicolor disk blackbody plus an additional high-energy power-law. Even though the spectra are very soft (Gamma approximately 2.5), RXTE detected a significant signal from LMC X-3 up to energies of 50 keV, the hardest energy at which the object was ever detected. Focusing on LMC X-3, we present results from the first year of an ongoing monitoring campaign with RXTE which started in 1997 January. We show that the appearance of the object changes considerably over its approximately 200d long cycle. This variability can either be explained by periodic changes in the mass transfer rate or by a precessing accretion disk analogous to Her X-1.

  2. RXTE Observation of Cygnus X-1. Report 2; TIming Analysis

    NASA Technical Reports Server (NTRS)

    Nowak, Michael A.; Vaughan, Brian A.; Wilms, Joern; Dove, James B.; Begelman, Mitchell C.

    1998-01-01

    We present timing analysis for a Rossi X-ray Timing Explorer (RXTE) observation of Cygnus X-1 in its hard/low state. This was the first RXTE observation of Cyg X-1 taken after it transited back to this state from its soft/high state. RXTE's large effective area, superior timing capabilities, and ability to obtain long, uninterrupted observations have allowed us to obtain measurements of the power spectral density (PSD), coherence function, and Fourier time lags to a decade lower in frequency and half a decade higher in frequency than typically was achieved with previous instruments. Notable aspects of our observations include a weak 0.005 Hz feature in the PSD coincident with a coherence recovery; a 'hardening' of the high-frequency PSD with increasing energy; a broad frequency range measurement of the coherence function, revealing rollovers from unity coherence at both low and high frequency; and an accurate determination of the Fourier time lags over two and a half decades in frequency. As has been noted in previous similar observations, the time delay is approximately proportional to f(exp -0.7), and at a fixed Fourier frequency the time delay of the hard X-rays compared to the softest energy channel tends to increase logarithmically with energy. Curiously, the 0.01-0.2 Hz coherence between the highest and lowest energy bands is actually slightly greater than the coherence between the second highest and lowest energy bands. We carefully describe all of the analysis techniques used in this paper, and we make comparisons of the data to general theoretical expectations. In a companion paper, we make specific comparisons to a Compton corona model that we have successfully used to describe the energy spectral data from this observation.

  3. Using the Process and Excitement of Science and Technology to Empower Teachers and Engage their Students

    NASA Technical Reports Server (NTRS)

    Crannell, Carol Jo

    2002-01-01

    Students United with NASA Becoming Enthusiastic About Math and Science (SUNBEAMS) is a Partnership between NASA Goddard Space Flight Center (GSFC) and the District of Columbia Public Schools (DCPS). It empowers teachers and inspires students with the process and excitement of science and technology. SUNBEAMS is being developed as a model urban intervention program for sixth grade teachers and their students. The teachers come to Goddard for five weeks during the summer. They partner with Goddard mentors and work much the same way that summer students do. In addition, the teachers are responsible for developing lesson plans that they pilot at their schools and post on the SUNBEAMS web site. During the school year, each teacher brings one class to Goddard for a full week of total immersion in math and science.

  4. OBSERVATIONS OF SOME X-RAY TRANSIENTS WITH RXTE

    SciTech Connect

    K. BOROZDIN; W. PRIEDHORSKY; ET AL

    1999-11-01

    We present results of observations of several X-ray transients with RXTE in 1996-1998, namely, GRS 1739-278, XTE J1748-288, GS 1354-64, 2S1803-245 and XTE J0421+560 (CI Cam). We studied light curves and spectra of their outbursts and compared them with observations of other X-ray transients. We discuss fits of high state spectra with BMC model, and similarities and differences between black holes and neutron stars in their low state. Special attention is paid to CI Cam as possible legate for new class of X-ray transients.

  5. XTE Observations of Intermediate Polars: RXTE TOO Observations of Supernovae

    NASA Technical Reports Server (NTRS)

    Schlegel, E.; Swank, Jean (Technical Monitor)

    2002-01-01

    Two intermediate polar cataclysmic variables, PQ Gem and AO Psc, were observed jointly with the Rossi X-ray Timing Explorer (RXTE) and ground-based photometry. The analysis of intermediate polars (IPs) is complex because these objects exhibit light curves that behave differently as a function of energy and that behave differently when phased on the orbital or on the spin periods. The presence of two periods in one system is essentially equivalent to analyzing two different X-ray sources. A preliminary analysis of the PQ Gem data was carried out and presented at the Annapolis Workshop on Magnetic Cataclysmic Variables. The final analysis of the data were held up by problems with the background estimation. The RXTE PCA team has released a new version of the background estimator. The PQ Gem must be reanalyzed using the new background. We have also installed a spectral model that calculates the expected emission from an accretion column. That model is undergoing final testing before we apply it to the data.

  6. Analysis of RXTE data on Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    Petrosian, Vahe

    2004-01-01

    This grant provided support for the reduction, analysis and interpretation of of hard X-ray (HXR, for short) observations of the cluster of galaxies RXJO658--5557 scheduled for the week of August 23, 2002 under the RXTE Cycle 7 program (PI Vahe Petrosian, Obs. ID 70165). The goal of the observation was to search for and characterize the shape of the HXR component beyond the well established thermal soft X-ray (SXR) component. Such hard components have been detected in several nearby clusters. distant cluster would provide information on the characteristics of this radiation at a different epoch in the evolution of the imiverse and shed light on its origin. We (Petrosian, 2001) have argued that thermal bremsstrahlung, as proposed earlier, cannot be the mechanism for the production of the HXRs and that the most likely mechanism is Compton upscattering of the cosmic microwave radiation by relativistic electrons which are known to be present in the clusters and be responsible for the observed radio emission. Based on this picture we estimated that this cluster, in spite of its relatively large distance, will have HXR signal comparable to the other nearby ones. The planned observation of a relatively The proposed RXTE observations were carried out and the data have been analyzed. We detect a hard X-ray tail in the spectrum of this cluster with a flux very nearly equal to our predicted value. This has strengthen the case for the Compton scattering model. We intend the data obtained via this observation to be a part of a larger data set. We have identified other clusters of galaxies (in archival RXTE and other instrument data sets) with sufficiently high quality data where we can search for and measure (or at least put meaningful limits) on the strength of the hard component. With these studies we expect to clarify the mechanism for acceleration of particles in the intercluster medium and provide guidance for future observations of this intriguing phenomenon by instrument on GLAST. The details of the nonthermal particle population has important implications for the theories of cluster formation, mergers and evolution. The results of this work were first presented at the High Energy Division meeting of the American astronomical Society at Mt. Tremblene, Canada (Petrosian et al. 2003). and in an invited review talk at the General Assembly of the International Astronomical Union at Sydney, Australia (Petrosian, 2003). A paper describe the observations, the data analysis and its implication is being prepared for publication in the Astrophysical Journal.

  7. Absolute Timing of the Crab Pulsar with RXTE

    NASA Technical Reports Server (NTRS)

    Rots, Arnold H.; Jahoda, Keith; Lyne, Andrew G.

    2004-01-01

    We have monitored the phase of the main X-ray pulse of the Crab pulsar with the Rossi X-ray Timing Explorer (RXTE) for almost eight years, since the start of the mission in January 1996. The absolute time of RXTE's clock is sufficiently accurate to allow this phase to be compared directly with the radio profile. Our monitoring observations of the pulsar took place bi-weekly (during the periods when it was at least 30 degrees from the Sun) and we correlated the data with radio timing ephemerides derived from observations made at Jodrell Bank. We have determined the phase of the X-ray main pulse for each observation with a typical error in the individual data points of 50 microseconds. The total ensemble is consistent with a phase that is constant over the monitoring period, with the X-ray pulse leading the radio pulse by 0.01025 plus or minus 0.00120 period in phase, or 344 plus or minus 40 microseconds in time. The error estimate is dominated by a systematic error of 40 microseconds, most likely constant, arising from uncertainties in the instrumental calibration of the radio data. The statistical error is 0.00015 period, or 5 microseconds. The separation of the main pulse and interpulse appears to be unchanging at time scales of a year or less, with an average value of 0.4001 plus or minus 0.0002 period. There is no apparent variation in these values with energy over the 2-30 keV range. The lag between the radio and X-ray pulses ma be constant in phase (i.e., rotational in nature) or constant in time (i.e., due to a pathlength difference). We are not (yet) able to distinguish between these two interpretations.

  8. Getting the Public Excited about Science through News Stories about Global Sporting Events

    NASA Astrophysics Data System (ADS)

    Dufoe, A.

    2014-12-01

    News is all about opportunity, and no topic can pull an audience together across ages and countries better than international sports competitions. Sports news excites people, generating conversations at work and at home throughout the duration of the competition. The popularity of these sporting events engages the general public through print and video channels, but it also offers the opportunity for news beyond the competition results - specifically, how science and scientific principles and properties tie in to the sport. Take the Olympics and the World Cup, for example. News sites were more motivated to write and run stories about the aerodynamics of a soccer ball or science behind Olympic bobsleds because these topics are timely: timeliness is one of the most important reasons news stories get written and published. And analysis of even a small sample of news stories and the language used will show why the news organization posted the story. Since the science content is being translated for the general public, the topics can provide a more general explanation of the science behind sporting events, equipment and the act of doing the sport. But beyond international sporting events, even the opening day of baseball, first night of ice hockey, the start of football and the beginning of basketball season provide opportunities for news organizations to provide science news to the public. Scientists need to get ready to collaborate with journalists to tap into the next big sporting event - Super Bowl XLIX. Although it has not been determined which teams are playing yet, scientists can start preparing content-rich stories on the physics of a football, the climate of Phoenix, Arizona, and the green mission of the University of Phoenix Stadium (the location of Super Bowl 2015). This is an opportunity for scientists and media outlets to add science content knowledge to the hype of the event. After the Super Bowl comes the 2016 Summer Olympics in Rio, which has already been in the news with reporters covering water contamination issues and sustainable construction projects.

  9. ADVANCES IN THE RXTE PROPORTIONAL COUNTER ARRAY CALIBRATION: NEARING THE STATISTICAL LIMIT

    SciTech Connect

    Shaposhnikov, Nikolai; Jahoda, Keith; Markwardt, Craig; Swank, Jean; Strohmayer, Tod

    2012-10-01

    During its 16 years of service, the Rossi X-Ray Timing Explorer (RXTE) mission has provided an extensive archive of data, which will serve as a primary source of high cadence observations of variable X-ray sources for fast timing studies. It is, therefore, very important to have the most reliable calibration of RXTE instruments. The Proportional Counter Array (PCA) is the primary instrument on board RXTE which provides data in 3-50 keV energy range with submillisecond time resolution in up to 256 energy channels. In 2009, the RXTE team revised the response residual minimization method used to derive the parameters of the PCA physical model. The procedure is based on the residual minimization between the model spectrum for Crab Nebula emission and a calibration data set consisting of a number of spectra from the Crab and the on-board Am{sub 241} calibration source, uniformly covering the whole RXTE mission operation period. The new method led to a much more effective model convergence and allowed for better understanding of the PCA energy-to-channel relationship. It greatly improved the response matrix performance. We describe the new version of the RXTE/PCA response generator PCARMF v11.7 (HEASOFT Release 6.7) along with the corresponding energy-to-channel conversion table (version e05v04) and their difference from the previous releases of PCA calibration. The new PCA response adequately represents the spectrum of the calibration sources and successfully predicts the energy of the narrow iron emission line in Cas-A throughout the RXTE mission.

  10. Advances in the RXTE Proportional Counter Array Calibration: Nearing the Statistical Limit

    NASA Technical Reports Server (NTRS)

    Shaposhnikov, Nikolai; Jahoda, Keith; Markwardt, Craig; Swank, Jean; Strohmayer, Tod

    2012-01-01

    During its 16 years of service Rossi X-ray Timing Explorer (RXTE) mission has provided an extensive archive of data, which will serve as a primary source of high cadence observation of variable X-ray sources for fast timing studies. It is, therefore, very important to have the most reliable calibration of RXTE instruments. The Proportional Counter Array (PCA) is the primary instrument on-board RXTE which provides data in 2-50 keY with higher than millisecond time resolution in up to 256 energy channels. In 2009 RXTE team revised the response residual minimization method used to derive the parameters of the PCA physical model. The procedure is now based on the residual minimization between the model spectrum for Crab nebula emission and a calibration data set consisting of a number of spectra from the Crab and the on-board Am241 calibration source, uniformly covering a whole RXTE span. The new method led to a much more effective model convergence and allowed for better understanding of the behavior of the PCA energy-to-channel relationship. It greatly improved the response matrix performance. We describe the new version of the RXTE/PCA response generator PCARMF vll.7 along with the corresponding energy-to-channel conversion table (version e05v04) and their difference from the previous releases of PCA calibration. The new PCA response adequately represents the spectrum of the calibration sources and successfully predicts the energy of the narrow iron emission line in Cas-A throughout the RXTE mission.

  11. Science Fair Competition Generates Excitement and Promotes Creative Thinking in Japan

    ERIC Educational Resources Information Center

    Barry, Dana M.; Kanematsu, Hideyuki

    2006-01-01

    Educators in the U.S. and Japan have developed an international program to promote creative thinking in science. Their program includes a science fair component. This paper (which has been presented in both the U.S. and Japan) discusses creativity and describes a science fair activity, that the authors recently carried out in Japan. The special…

  12. The Excitement and Wonder of Teaching Science: What Pre-Service Teachers Learn from Facilitating Family Science Night Centers

    ERIC Educational Resources Information Center

    Harlow, Danielle B.

    2012-01-01

    In this study, pre-service teachers facilitated stations at a family science night as a context to learn to identify, assess, and use children's science ideas. Assessment is already difficult in K-12 classrooms. Assessing learning in informal learning environments adds the complication that participation is largely voluntary. As such, controlling…

  13. The Excitement and Wonder of Teaching Science: What Pre-service Teachers Learn from Facilitating Family Science Night Centers

    NASA Astrophysics Data System (ADS)

    Harlow, Danielle B.

    2012-02-01

    In this study, pre-service teachers facilitated stations at a family science night as a context to learn to identify, assess, and use children's science ideas. Assessment is already difficult in K-12 classrooms. Assessing learning in informal learning environments adds the complication that participation is largely voluntary. As such, controlling the learners' participation to systematically assess learning is counter to the intents of informal environments. The pre-service teachers in this study experienced success at teaching science and developed understandings about children's science ideas. Data included reflective postings, class discussions, observations, artifacts, and photographs. The findings contribute to understanding the value of multiple learning contexts in teacher preparation and lead to implications about leveraging informal science contexts for educating teachers.

  14. A Coordinated RXTE/ASCA Study of Absorption Dips in Circinus X-1 at Phase Zero

    NASA Technical Reports Server (NTRS)

    Bradt, Hale

    2000-01-01

    This proposal was for an Rossi X Ray Timing Explorer (RXTE) study of Circinus X-1 with the ASCA satellite for the purpose of studying the iron emission feature during intensity dips. These dips had been discovered previously with ASCA and they appeared to vary in equivalent width and in the energy of the iron K edge. Proper analyses requires good continuum measurements which Rossi X Ray Timing Explorer/Proportional Counter Array (RXTE/PCA) could provide. Also, the PCA data would show any temporal evolution correlated with spectral evolution. RXTE provided 90 ks of data during March 3-5, 1998 which included phase zero which is where the dips usually take place. The ASCA observations were taken by Dr. Neil Brandt of Penn State University. Unfortunately, the source intensity showed far less dipping activity than is typical near phase zero. The light curve exhibited only very narrow sporadic dips rather than some long deep dips necessary for sufficient statistics in the ASCA and RXTE instruments for spectral studies. This prevented us from carrying out the primary goal of the proposal.

  15. Using the Unconventional Stellar Aspect (USA) and the Rossi X-ray Timing Explorer (RXTE) Experimental Data to Determine Atmospheric Composition, Density, and Temperature

    NASA Astrophysics Data System (ADS)

    Determan, J. R.; Budzein, S. A.; Titarchuk, L.

    2002-05-01

    The X-ray Astronomy Branch of the Naval Research Laboratory launched the Unconventional Stellar Aspect (USA) experiment aboard the Advanced Research and Global Observation Satellite (ARGOS) in 1999. USA is an X-ray timing experiment with a large collecting area and microsecond time resolution capable of conducting a broad program of studies of galactic X-ray binaries. USA consists of a collimated proportional counter X-ray telescope and two detectors with ~1000 cm2 effective area each, sensitive to photons in the 1-15 keV energy range. The Rossi X-ray Timing Explorer (RXTE) was launched on December 30, 1995 from NASA's Kennedy Space Center. The mission is managed and controlled by NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. RXTE features unprecedented time resolution in combination with moderate spectral resolution to explore the variability of X-ray sources. Time scales from microseconds to months are covered in an instantaneous spectral range from 2 to 250 keV. We have developed a new technique to measure the composition and structure of the upper atmosphere using atmospheric occultation of celestial x-ray sources. Both USA and RXTE provide energy-resolved photon extinction curves, and the combined energy ranges of USA and RXTE permit direct probing of the mesosphere and lower thermosphere (80-160 km). Roughly speaking, differential absorption among energy bands can provide composition information, and the shape of the light curves total density versus altitude. Two complementary algorithms have been employed in the data analysis. The first method employs basis functions derived from NRLMSIS-00 (Picone et al 2000) in a Discrete Inverse Theory maximum likelihood retrieval of densities and temperature by fitting the light curve. The second method is a direct inversion of the light curve to determine optical depths and optical depth scale height, from which temperature and density may be iteratively derived in a self-consistent manner from NRLMSIS-00 composition information. The results from both methods are compared to each other, standard atmospheric models, and data from the High Resolution Airglow and Aurora Spectrograph (HIRAAS), mounted alongside USA on the ARGOS satellite. This research is the first to study the neutral atmosphere in this energy range, and complements UV airglow remote sensing techniques used aboard ARGOS that are less sensitive to nighttime neutral density. Enhanced Empirical Models of the Thermosphere, J. M. Picone, A. E.Hedin, D. P. Drob, R. R. Meier, J. Lean, A. C. Nicholas, and S. E. Thonnard, Physics and Chemistry of the Earth, Part C: Solar-Terrestrial and Planetary Science, 25(5-6), 537-42 (2000). Keywords: upper atmosphere, X-rays, horizon crossing, occultations

  16. An interdisciplinary national program developed at Baylor to make science exciting for all K-5 students.

    PubMed

    Moreno, N P; Tharp, B Z

    1999-04-01

    The achievement gap in science begins in elementary school, where many students lose interest in science-related studies, particularly students from traditionally underrepresented groups. The "My Health My World" Project (hereafter, "the Project"), developed at Baylor College of Medicine with the assistance of federal funds, is a national effort to address this problem. The Project's goals are to make science appealing and relevant for elementary school students (i.e., kindergarten through grade five), including those from underrepresented minorities (URMs), and easy to teach for teachers and parents. It is achieving this goal by the development of interdisciplinary instructional materials that use environmental health issues as a unifying theme. The Project provides its materials (including take-home materials for parents) and training for teachers at seven dissemination centers across the country, established in 1997. Workshops are also held to train facilitators, chosen from among local science education leaders, who in turn hold workshops to train other teachers. Each center receives a mini-grant to cover costs related to the training it provides, and all coordinate their training to offer comparable experiences for all participants. Field tests in 1995, 1996, and 1997 involving culturally, racially, and ethnically diverse students and teachers in two sites indicate that the participating teachers found that the Project's materials promote science learning and enthusiasm for science and are easy to use and engaging for teachers. Ratings for workshops in 1998 were also high for all characteristics evaluated. All signs after the Project's first full year of dissemination activities (1998) indicate that it will continue to reach more teachers and students across the nation and will eventually help more students from all backgrounds achieve in science-related studies. PMID:10219206

  17. RXTE, Chandra, and XMM Spectroscopy of the Fe-K Lines and Compton Reflection in Type 1 AGN

    NASA Technical Reports Server (NTRS)

    Yaqoob, Tahir

    2004-01-01

    This award pertains to an RXTE observation of the Seyfert 1 galaxy Akn 120. The purpose of the observation was to measure the Fe-K emission line and the Compton reflection continuum with RXTE, simultaneously with Chandra and XMM. Such measurements can severely constrain accretion disk models of the central engine since the Fe-K line emission and Compton reflection are intimately related in terms of the physics of X-ray reprocessing in optically-thick matter. Akn 120 was selected for this study because it is amongst the brightest AGN in its class and has a particularly strong and apparently broad Fe-K emission line. The results could then also be used to lay the ground work for even higher resolution studies with Astro-E2. Unfortunately, the Chandra observation was not performed but a contemporaneous XMM observation was performed by another group of researchers. Those data recently became public and can be compared with the RXTE data. In addition, non-contemporaneous observations with other missions do still provide additional important constraints (for example any non-varying line or continuum emission components can be established and used to reject or preserve various model scenarios). We analyzed the RXTE data and found a strong Fe-K emission line (resolved even with the poor resolution of RXTE), and a strong Compton-reflection continuum (see Fig. l(a)). We found that the results of archival ASCA data on Akn 120 had not been published in the literature so we analyzed the ASCA data too, in order to compare with the new RXTE data. Fig. l(b) shows that the ASCA data also reveal a strong, broad FeK emission line (but the data are not sensitive to the Compton-reflection continuum). We compared our spectral fitting results for the RXTE and ASCA data with the results from XMM and from previous RXTE observations.

  18. Swift, INTEGRAL, RXTE, and Spitzer Reveal IGR J16283-4838

    NASA Technical Reports Server (NTRS)

    Beckmann, V.; Gehrels, N.; Markwardt, C.; Barthelmy S.; Soldi, S.; Paizis, A.; Mowlavi, N.; Kennca, J. A.; Burrows, D. N.; Chester, M.

    2005-01-01

    We present the first combined study of the recently discovered source IGR J16283-4838 with Swift, INTEGRAL, and RXTE. The source, discovered by INTEGRAL on April 7, 2005, shows a highly absorbed (variable N(sub H) = 0.4-1.7 x 10(exp 23) /sq cm) and flat (Gamma approx. 1) spectrum in the Swift/XRT and RXTE/PCA data. No optical counterpart is detectable (V > 20 mag), but a possible infrared counterpart within the Swift/XRT error radius is detected in the 2MASS and Spitzer/GLIMPSE survey. The observations suggest that IGR J16283-4838 is a high mass X-ray binary containing a neutron star embedded in Compton thick material. This makes IGR J16283-4838 a member of the class of highly absorbed HMXBs, discovered by INTEGRAL.

  19. Observation of Nonthermal Emission from the Supernova Remnant IC443 with RXTE

    NASA Technical Reports Server (NTRS)

    Sturner, S. J.; Keohane, J. W.; Reimer, O.

    2002-01-01

    In this paper we present analysis of X-ray spectra from the supernova remnant IC443 obtained using the PCA on RXTE. The spectra in the 3 - 20 keV band are well fit by a two-component model consisting of thermal and nonthermal components. We compare these results with recent results of other X-ray missions and discuss the need for a cut-off in the nonthermal spectrum. Recent Chandra and XMM-Newton observations suggest that much of the nonthermal emission from IC443 can be attributed to a pulsar wind nebula. We present the results of our search for periodic emission in the RXTE PCA data. We then discuss the origin o f the nonthermal component and its possible association with the unidentified EGRET source.

  20. Joint XMM-Newton, Chandra, and RXTE Observations of Cyg X-1 at Phase Zero

    NASA Technical Reports Server (NTRS)

    Pottschmidt, Katja

    2008-01-01

    We present first results of simultaneous observations of the high mass X-ray binary Cyg X-1 for 50 ks with XMM-Newton, Chandra-HETGS and RXTE in 2008 April. The observations are centered on phase 0 of the 5.6 d orbit when pronounced dips in the X-ray emission from the black hole are known to occur. The dips are due to highly variable absorption in the accretion stream from the O-star companion to the black hole. Compared to previous high resolution spectroscopy studies of the dip and non-dip emission with Chandra, the addition of XMM-Newton data allows for a better determination of the continuum, especially through the broad iron line region (with RXTE constraining the greater than 10 keV continuum).

  1. Life in the Universe: Foundation for exciting multidisciplinary science activities for middle and elementary school classes

    NASA Technical Reports Server (NTRS)

    Milne, D.; O'Sullivan, K.

    1994-01-01

    Young students find extra-terrestrial life one of the most intriguing of all topics. A project funded by the National Science Foundation and NASA, and administered by the SETI Institute, is underway to devise science lessons for grades 3-9 that draw upon this fascination. The lessons are designed by teachers and persons with long experience at curriculum design, tested in classrooms, revised and retested. Six guides, each containing some 6-10 science lessons, will be finished by summer, 1994.The theme Life in the Universe lends itself naturally to integrated treatment of facts and concepts from many scientific disciplines. The lessons for two completed guides span the origin of planet systems, evolution of complex life, chemical makeup of life, astronomy, spectroscopy, continental drift, mathematics and SETI (Search for Extra-Terrestrial Intelligence). All lessons are hands-on, interesting, and successful.

  2. Life in the universe: Foundation for exciting multidisciplinary science activities for middle and elementary school classes

    NASA Astrophysics Data System (ADS)

    Milne, D.; O'Sullivan, K.

    1994-08-01

    Young students find extra-terrestrial life one of the most intriguing of all topics. A project funded by the National Science Foundation and NASA, and administered by the SETI Institute, is underway to devise science lessons for grades 3-9 that draw upon this fascination. The lessons are designed by teachers and persons with long experience at curriculum design, tested in classrooms, revised and retested. Six guides, each containing some 6-10 science lessons, will be finished by summer, 1994. The theme Life in the Universe lends itself naturally to integrated treatment of facts and concepts from many scientific disciplines. The lessons for two completed guides span the origin of planet systems, evolution of complex life, chemical makeup of life, astronomy, spectroscopy, continental drift, mathematics and SETI (Search for Extra-Terrestrial Intelligence). All lessons are hands-on, interesting, and successful.

  3. INTEGRAL and RXTE observations of XTE J1946+274 in outburst

    NASA Astrophysics Data System (ADS)

    Caballero, I.; Pottschmidt, K.; Bozzo, E.; Ferrigno, C.; Neronov, A.; Santangelo, A.; Klochkov, D.; Staubert, R.; Kretschmar, P.; Wilms, J.; Kreykenbohm, I.; Fuerst, F.; Schoenherr, G.; Rothschild, R.; Suchy, S.

    2010-06-01

    The Be/X-ray binary XTE J1946+274 is undergoing an X-ray outburst that started on 2010 June 04 and has been observed by Swift and Fermi GBM (ATels #2663, #2677). The source was discovered in 1998 during a giant outburst with ASM/RXTE and BATSE/CGRO (Smith & Takeshima 1998, Wilson et al. 1998), and remained active until 2001 when it started a quiescence phase, interrupted only by the current outburst.

  4. RXTE and Swift Observations of SWIFT J0513.4-6547

    NASA Astrophysics Data System (ADS)

    Şahiner, Ş.; Serim, M. M.; Baykal, A.; İnam, S. Ç.

    2016-02-01

    We present timing and spectral analysis of Swift-XRT (X-ray Telescope) and RXTE-PCA (Rossi X-ray Timing Explorer-proportional Counter Array) observations of the transient Be/X-ray pulsar SWIFT J0513.4-6547 during its outburst in 2009 and its rebrightening in 2014. From 2009 observations, short-term spin-up rate of the source after the peak of the outburst is found to have about half of the value measured at the peak of the outburst by Coe et al. When the source is quiescent between 2009 and 2014, average spin-down rate of the source is measured to be ˜1.52 × 10-12 Hz s-1 indicating a surface dipole magnetic field of ˜1.5 × 1013 G assuming a propeller state. From 2014 observations, short-term spin-down rate of the source is measured to be about two orders smaller than this long-term spin-down rate. The orbit of the source is found to be circular which is atypical for transient Be/X-ray binary systems. Hardness ratios of the source correlate with the X-ray luminosity up to 8.4 × 1036 erg s-1 in the 3-10 keV band, whereas for higher luminosities hardness ratios remain constant. Pulsed fractions are found to be correlated with the source flux. Overall Swift-XRT and RXTE-PCA energy spectrum of the source fit equally well to a model consisting of blackbody and power law, and a model consisting of a power law with high-energy cut-off. From the pulse phase-resolved spectra and pulse phase-resolved hardness ratios obtained using RXTE-PCA, it is shown that spectrum is softer for the phases between the two peaks of the pulse.

  5. ASCA and Radio/RXTE Observations of GX 339-4

    NASA Technical Reports Server (NTRS)

    Nowak, M. A.; Wilms, J.; Dove, J. B.; Fender, R. P.

    1999-01-01

    We have analyzed three separate archival Advanced Satellite for Cosmology and Astrophysics (ASCA) observations and eight separate Rossi X-ray Timing Explorer (RXTE) observations of the black hole candidate GX 339-4 in its low luminosity, spectrally hard state. Three of the RXTE observations were strictly simultaneous with 843 MHz and 8.3- 9.1 GHz radio observations. All data sets show evidence for an approximately 6.4 keV Fe line with equivalent widths approximately 20-100 eV. 'Reflection models' show a hardening of the RXTE spectra with decreasing X-ray flux; however, these models do not exhibit evidence of a correlation between the photon index of the incident power law flux and the solid angle subtended by the reflector. None of the models fit to the X-ray data, however, simultaneously explain the observed radio properties. We argue that the spatial extent of the observed radio emission is at least 0(10(exp 7 GM/c squared). Timing analysis reveals that all observations save one show evidence of a persistent f(qpo approximately equals 0.3 Hz quasi-periodic oscillations(quasi-periodic oscillations)). The broad band (10-3-102 Hz) power appears to be dominated by two independent processes that can be modeled as very broad Lorentzians with Q approximately less than 1. Similar to Cyg X-1, the hard photon variability is seen to lag the soft photon vaxiability with the lag time increasing with decreasing Fourier frequency. The magnitude of this time lag is seen to be positively correlated with the flux of GX 339-4.

  6. RXTE Detection of the Spin Period of Swift J1822.3-1606

    NASA Astrophysics Data System (ADS)

    Gogus, Ersin; Kouveliotou, Chryssa; Strohmayer, Tod

    2011-07-01

    RXTE/PCA observed the new source, Swift J1822.3-1606 (Cummings et al. GCN Circ. 12159) on 2011 July 16, for 6.7 ks. We performed a timing analysis on the barycentered data and detected a coherent pulsation at 0.1185149(2) Hz corresponding to 8.4377585 s. Pulsations are clearly visible in the PCA light curve. The peak-to-peak pulsed amplitude in the 2-10 keV band is 0.41. This pulsed fraction is highly unlikely from an SGR source, and very reminiscent of the outburst onset of Swift J1626.6-5156 (Palmer et al.

  7. INTEGRAL and RXTE Observations of Broad-Line Radio Galaxy 3C 111

    NASA Astrophysics Data System (ADS)

    Chernyakova, M.; Favre, P.; Courvoisier, T. J.-L.; Lutovinov, A.; Molkov, S.; Beckmann, V.; Gros, A.; Gehrels, N.; Prodiut, N.; Walter, R.; Zdziarski, A.

    2004-10-01

    3C 111 is an X-ray bright broad-line radio galaxy which is classified as a Fanaroff-Riley type II source with a double-lobe/single jet morphology, and re- ported superluminal motion. It is a well-known X- ray source, and was observed by every major X-ray observatory since HEAO-1. In this paper we present the results of the RXTE and INTEGRAL data anal- ysis and compare them with the results of the previ- ous observations. Key words: X rays: radio galaxies; X rays: individ- uals: 3C 111.

  8. A bright thermonuclear X-ray burst simultaneously observed with Chandra and RXTE

    NASA Astrophysics Data System (ADS)

    in't Zand, J. J. M.; Galloway, D. K.; Marshall, H. L.; Ballantyne, D. R.; Jonker, P. G.; Paerels, F. B. S.; Palmer, D. M.; Patruno, A.; Weinberg, N. N.

    2013-05-01

    The prototypical accretion-powered millisecond pulsar SAX J1808.4-3658 was observed simultaneously with Chandra-LETGS and RXTE-PCA near the peak of a transient outburst in November 2011. A single thermonuclear (type-I) burst was detected, the brightest yet observed by Chandra from any source, and the second-brightest observed by RXTE. We found no evidence for discrete spectral features during the burst; absorption edges have been predicted to be present in such bursts, but may require a greater degree of photospheric expansion than the rather moderate expansion seen in this event (a factor of a few). These observations provide a unique data set to study an X-ray burst over a broad bandpass and at high spectral resolution (λ/Δλ = 200-400). We find a significant excess of photons at high and low energies compared to the standard black body spectrum. This excess is well described by a 20-fold increase of the persistent flux during the burst. We speculate that this results from burst photons being scattered in the accretion disk corona. These and other recent observations of X-ray bursts point out the need for detailed theoretical modeling of the radiative and hydrodynamical interaction between thermonuclear X-ray bursts and accretion disks.

  9. RXTE Spectral Study of the New X-ray Transient XTE J1859+226

    NASA Astrophysics Data System (ADS)

    Focke, W. B.; Markwardt, C. B.; Swank, J. H.; Taam, R. E.

    1999-12-01

    The transient galactic black hole candidate XTE J1859+226 was discovered by the RXTE All Sky Monitor (ASM) on 1999 October 9, within a day after its outburst began. Pointed observations with RXTE began on 1999 October 10.57, and continued at a rate of about twice per day. Preliminary results of fits to PCA and HEXTE spectra for October 9--14 show that a simple absorbed powerlaw is insufficient to model the data. The fit is greatly improved by using an absorbed cutoff powerlaw with reflection. The photon index rose from 1.8 on October 9 to 3.2 on October 14. The cutoff energy started near 100 keV, dropped to 50 keV, then rose to an undetectable level between October 12.86 and October 13.11, potentially indicating a state change. We will present spectral analysis of these and later data, along with comparison of the spectral and timing properties. This work was funded by NASA.

  10. MULTIWAVELENGTH OBSERVATIONS OF LS I +61{sup 0} 303 WITH VERITAS, SWIFT, AND RXTE

    SciTech Connect

    Acciari, V. A.; Aliu, E.; Arlen, T.; Chow, Y. C.; Bautista, M.; Cogan, P.; Beilicke, M.; Bugaev, V.; Benbow, W.; Boettcher, M.; Bradbury, S. M.; Daniel, M.; Butt, Y.; Butt, Y.; Byrum, K.; Cannon, A.; Cesarini, A.; Ciupik, L.; Colin, P.; Cui, W.

    2009-08-01

    We present results from a long-term monitoring campaign on the TeV binary LSI +61{sup 0} 303 with VERITAS at energies above 500 GeV, and in the 2-10 keV hard X-ray bands with RXTE and Swift, sampling nine 26.5 day orbital cycles between 2006 September and 2008 February. The binary was observed by VERITAS to be variable, with all integrated observations resulting in a detection at the 8.8{sigma} (2006/2007) and 7.3{sigma} (2007/2008) significance level for emission above 500 GeV. The source was detected during active periods with flux values ranging from 5% to 20% of the Crab Nebula, varying over the course of a single orbital cycle. Additionally, the observations conducted in the 2007-2008 observing season show marginal evidence (at the 3.6{sigma} significance level) for TeV emission outside the apastron passage of the compact object around the Be star. Contemporaneous hard X-ray observations with RXTE and Swift show large variability with flux values typically varying between 0.5 and 3.0 x10{sup -11} erg cm{sup -2} s{sup -1} over a single orbital cycle. The contemporaneous X-ray and TeV data are examined and it is shown that the TeV sampling is not dense enough to detect a correlation between the two bands.

  11. An Empirical Method for Improving the Quality of RXTE HEXTE Spectra

    NASA Astrophysics Data System (ADS)

    García, Javier A.; Grinberg, Victoria; Steiner, James F.; McClintock, Jeffrey E.; Pottschmidt, Katja; Rothschild, Richard E.

    2016-03-01

    We have developed a correction tool to improve the quality of Rossi X-ray Timing Explorer (RXTE) High Energy X-ray Timing Experiment (HEXTE) spectra by employing the same method we used earlier to improve the quality of RXTE Proportional Counter Array (PCA) spectra. We fit all of the hundreds of HEXTE spectra of the Crab individually to a simple power-law model, some 37 million counts in total for Cluster A and 39 million counts for Cluster B, and we create for each cluster a combined spectrum of residuals. We find that the residual spectrum of Cluster A is free of instrumental artifacts while that of Cluster B contains significant features with amplitudes ∼1% the most prominent is in the energy range 30–50 keV, which coincides with the iodine K edge. Starting with the residual spectrum for Cluster B, via an iterative procedure we created the calibration tool hexBcorr for correcting any Cluster B spectrum of interest. We demonstrate the efficacy of the tool by applying it to Cluster B spectra of two bright black holes, which contain several million counts apiece. For these spectra, application of the tool significantly improves the goodness of fit, while affecting only slightly the broadband fit parameters. The tool may be important for the study of spectral features, such as cyclotron lines, a topic that is beyond the scope of this paper.

  12. Low Luminosity States of the Black Hole Candidate GX 339-4. 1; ASCA and Simultaneous Radio/RXTE Observations

    NASA Technical Reports Server (NTRS)

    Wilms, Joern; Nowak, Michael A.; Dove, James B.; Fender, Robert P.; DiMatteo, Tiziana

    1998-01-01

    We discuss a series of observations of the black hole candidate GX 339-4 in low luminosity, spectrally hard states. We present spectral analysis of three separate archival Advanced Satellite for Cosmology and Astrophysics (ASCA) data sets and eight separate Rossi X-ray Timing Explorer (RXTE) data sets. Three of the RXTE observations were strictly simultaneous with 843 Mega Hertz and 8.3-9.1 Giga Hertz radio observations. All of these observations have (3-9 keV) flux approximately less than 10(exp-9) ergs s(exp-1) CM(exp -2). The ASCA data show evidence for an approximately 6.4 keV Fe line with equivalent width approximately 40 eV, as well as evidence for a soft excess that is well-modeled by a power law plus a multicolor blackbody spectrum with peak temperature approximately equals 150-200 eV. The RXTE data sets also show evidence of an Fe line with equivalent widths approximately equal to 20-1OO eV. Reflection models show a hardening of the RXTE spectra with decreasing X-ray flux; however, these models do not exhibit evidence of a correlation between the photon index of the incident power law flux and the solid angle subtended by the reflector. 'Sphere+disk' Comptonization models and Advection Dominated Accretion Flow (ADAF) models also provide reasonable descriptions of the RXTE data. The former models yield coronal temperatures in the range 20-50 keV and optical depths of r approximately equal to 3. The model fits to the X-ray data, however, do not simultaneously explain the observed radio properties. The most likely source of the radio flux is synchrotron emission from an extended outflow of extent greater than O(10 (exp7) GM/c2).

  13. RXTE-ASM detects the start of a possible state transition in Cygnus X-1

    NASA Astrophysics Data System (ADS)

    Rushton, A.; Dhawan, V.; Fender, R.; Garrett, M.; Maccarone, T.; Miller-Jones, James; Paragi, Z.; Pooley, G.; Spencer, R.; Tudose, V.

    2010-07-01

    Recent data from the All Sky Monitor (ASM) onboard the RXTE satellite has detected an increase in X-rays within the 2-12 keV band. The ASM measured an increase in X-rays starting around 23 June 2010 (MJD 55370) and peaking on 1 July 2010 (MJD 55377.8) with a brightness of 51.92 c/s (688 mCrab) and HR2 = 1.088. In-addition, monitoring with the SWIFT-BAT (15-150 keV) has shown no significant increase, but radio observations with the AMI radio interferometer (15 GHz), have not yet shown any significant radio flaring either.

  14. Monitoring RXTE observations of Markarian 348: the origin of the column density variations

    NASA Astrophysics Data System (ADS)

    Akylas, A.; Georgantopoulos, I.; Griffiths, R. G.; Papadakis, I. E.; Mastichiadis, A.; Warwick, R. S.; Nandra, K.; Smith, D. A.

    2002-05-01

    We analyse 37 RXTE observations of the type 2 Seyfert galaxy Mrk 348 obtained over a period of 14 months. We confirm the spectral variability previously reported by Smith, Georgantopoulos & Warwick, in the sense that the column density decreases by a factor of ~3 as the count rate increases. Column density variations could possibly originate either from the random drift of clouds within the absorption screen, or from photoionization processes. Our modelling of the observed variations implies that the first scenario is more likely. These clouds should lie within a distance of >2 light-years from the source, having a diameter of a few light-days and a density of >107 cm-3 , hence probably residing outside the broad-line region.

  15. Peculiar Outburst of A 0535+26 Observed with INTEGRAL, RXTE and Suzaku

    NASA Technical Reports Server (NTRS)

    Caballero, I.; Pottschmidt, K.; Barragan, L.; Ferrigno, C.; Kretschmar, P.; Suchy, S.; Wilms, J.; Santangelo, A.; Kreykenbohm, I.; Rothschild, R.; Klochkov, D.; Staubert, R.; Finger, M. H.; Camero-Arranz, A.; Makishima, K.; Enoto, T.

    2009-01-01

    A normal outburst of the Be/X-ray binary system A0535+26 has taken place in August 2009. It is the fourth in a series of normal outbursts that have occurred around the periastron passage of the source. but is unusual by starting at an earlier orbital phase and by presenting a peculiar double-peaked light curve. A first "flare" (lasting about 9 days from M.ID 55043 on) reached a flux of 440 mCrab. The flux then decreased to less than 220 mCrab. and increased again reaching 440 mCrab around the periastron at MJD 55057. Target of Opportunity observations have been performed with INTEGRAL. RXTE and Suzaku. First results of these observations are presented. with special emphasis on the cyclotron lines present in the X-ray spectrum of the source. as well as in the pulse period and energy dependent pulse profiles of the source

  16. Neutron Stars and Black Holes Seen with the Rossi X-Ray Timing Explorer (RXTE)

    NASA Technical Reports Server (NTRS)

    Swank, Jean

    2008-01-01

    Astrophysical X-rays bring information about location, energy, time, and polarization. X-rays from compact objects were seen in the first explorations to vary in time. Eclipses and pulsations have simple explanations that identified the importance of X-ray binaries and magnetic neutron stars in the first decade of X-ray astronomy. The dynamics of accretion onto stellar and supermassive black holes and onto neutron stars with relatively low magnetic fields shows up as more complex variations, quasi-periodic oscillations, noise with characteristic frequency spectra, broad-band changes in the energy spectra. To study these variations, RXTE instruments needed to have large area and operational flexibility to find transient activity and observe when it was present. Proportional counters and Phoswich scintillators provided it in a modest mission that has made textbook level contributions to understanding of compact objects. The first seen, and the brightest known, X-ray binary, Sco X-1 is one of a class of neutron stars with low mass companions. Before RXTE, none of these had been seen to show pulsations, though they were hypothesized to be the precursors of radio pulsars with millisecond periods and low magnetic fields. RXTE's large area led to identifying coherent millisecond pulsars in a subset which are relatively faint transients. It also led to identifying short episodes of pulsation during thermonuclear bursts, in sources where a steady signal is not seen. The X-ray stage verifies the evolution that produces millisecond radio pulsars.Masses and radii of neutron stars are being determined by various techniques, constraining the equation of state of matter at nuclear densities. Accretion should lead to a range of neutron star masses. An early stage of superstrong magnetic field neutron stars is now known to produce X-ray and gamma-ray bursts in crust quakes and magnetic field reconnection releases of energy. Soft Gamma Repeaters, Anomolous X-ray Pulsars, and high magnetic field rotation-powered pulsars are all now called magnetars, because they have pulse periods indicating they are slowing down as they would with magnetic dipole radiation for a surface field above 5x1013 gauss. The accretion disk has been connected to the launching of radio jets from black holes, and even from neutron stars. Estimates of the angular momenta of black holes are being made from different approaches, modelling a high frequency oscillation that may be related to how close the inner part of the accretion disk is to the black hole, modelling the continua spectra of the X-ray emission, and modeling the emission of red-shifted iron that may be emitted from the accretion disk. These investigations require early discovery of the black hole transient with the All Sky Monitor on RXTE or other monitoring information, frequent extended observations, and coordinated observations with missions that give higher energy resolution, or radio and infrared information.

  17. RXTE Observations of A1744-361: Correlated Spectral and Timing Behavior

    NASA Technical Reports Server (NTRS)

    Bhattacharyya, Sudip; Strohmayer, Tod E.; Swank, Jean H.; Markwardt, Craig B.

    2007-01-01

    We analyze Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) data of the transient low mass X-ray binary (LMXB) system A1744-361. We explore the X-ray intensity and spectral evolution of the source, perform timing analysis, and find that A1744-361 is a weak LMXB, that shows atoll behavior at high intensity states. The color-color diagram indicates that this LMXB was observed in a low intensity spectrally hard (low-hard) state and in a high intensity banana state. The low-hard state shows a horizontal pattern in the color-color diagram, and the previously reported dipper QPO appears only during this state. We also perform energy spectral analyses, and report the first detection of broad iron emission line and iron absorption edge from A1744-361.

  18. A DOUBLE-PEAKED OUTBURST OF A 0535+26 OBSERVED WITH INTEGRAL, RXTE, AND SUZAKU

    SciTech Connect

    Caballero, I.; Barragan, L.; Wilms, J.; Kreykenbohm, I.; Ferrigno, C.; Klochkov, D.; Suchy, S.; Santangelo, A.; Staubert, R.; Zurita Heras, J. A.; Kretschmar, P.; Fuerst, F.; Rothschild, R.; Finger, M. H.; Camero-Arranz, A.; Makishima, K.; Enoto, T.; Iwakiri, W.; and others

    2013-02-20

    The Be/X-ray binary A 0535+26 showed a normal (type I) outburst in 2009 August. It is the fourth in a series of normal outbursts associated with the periastron, but is unusual because it presented a double-peaked light curve. The two peaks reached a flux of {approx}450 mCrab in the 15-50 keV range. We present results of the timing and spectral analysis of INTEGRAL, RXTE, and Suzaku observations of the outburst. The energy-dependent pulse profiles and their evolution during the outburst are studied. No significant differences with respect to other normal outbursts are observed. The centroid energy of the fundamental cyclotron line shows no significant variation during the outburst. A spectral hardening with increasing luminosity is observed. We conclude that the source is accreting in the sub-critical regime. We discuss possible explanations for the double-peaked outburst.

  19. The Crab Pulsar Observed by RXTE: Monitoring the X-Ray to Radio Delay for 16 Years

    NASA Technical Reports Server (NTRS)

    Rots, Arnold; Jahoda, Keith

    2012-01-01

    In 2004 we published the results of monitoring the Crab Pulsar by RXTE. At that time we determined that the primary pulse of the pulsar at X-ray energies precedes its radio counterpart by about 0.01 period in phase or approximately 330 micro seconds. However, we could not establish unambiguously whether the delay is in phase or due to a difference in pathlength. At this time we have twice the time baseline we had in 2004 and we present the same analysis, but now over a period of 16 years, which will represent almost the full mission and the best that will be available from RXTE. The full dataset shows that the phase delay has been decreasing faster than the pulse frequency over the 16 year baseline and that there are variations in the delay on a variety of timescales.

  20. Exploring Blazar Jets through Multiwaveband Monitoring with RXTE, the VLBA, and Other Instruments

    NASA Astrophysics Data System (ADS)

    Marscher, A. P.; Jorstad, S. G.; Aller, M. F.; McHardy, I. M.

    2005-12-01

    We have compiled over the past decade well-sampled light curves of several blazars with RXTE, the University of Michigan Radio Astronomy Observatory, Lowell Observatory, and the Liverpool Telescope, supplemented by data from many other telescopes supplied by collaborators. Over the same time span, we have followed changes in the parsec-scale jets through monthly or bimonthly imaging in both total and polarized intensity at 43 GHz (7 mm) with the VLBA. The X-ray flux varies on all sampled time scales, with power spectral densities corresponding to red noise. It is clear that the X-ray variations are correlated with those at lower frequencies. The correlations are complex, owing to gradients and inhomogeneities in the physical conditions of the emission regions, as well as to changes in the Doppler beaming factor caused by swings in the direction of the compact jet and possibly fluctuations in the bulk Lorentz factor of the jet flow. An unanticipated result is the existence of a time delay between changes in the synchrotron flux at lower frequencies and the X-ray variations. The X-rays therefore mostly come from regions in the jet that also produce optical and, at least in one quasar (PKS 1510-089), radio emission. The correlations of the multiwaveband light curves, along with separately discovered correlations in mm-wave to optical polarization direction, provide a new method for mapping the multiwaveband emission in blazars. Through simultaneous monitoring of polarization at mm, near-IR, and optical wavelengths as well as polarization imaging with the VLBA at 7 mm, we can establish which feature in the mm-wave jet is responsible for the higher frequency emission and can determine the timing between events in the same feature at different wavelengths. We can use the correlations of variations in total flux to relate flares at these higher synchrotron frequencies to X-ray flares, thereby pinpointing the locations of the emission from radio to X-ray frequencies. We will show preliminary results from our program that apply this technique. This work is based on research supported by NASA through the RXTE Guest Investigator Program and by NSF through grants to Boston U. and U. Michigan.

  1. Results of WEBT, VLBA and RXTE monitoring of 3C 279 during 2006-2007

    NASA Astrophysics Data System (ADS)

    Larionov, V. M.; Jorstad, S. G.; Marscher, A. P.; Raiteri, C. M.; Villata, M.; Agudo, I.; Aller, M. F.; Arkharov, A. A.; Asfandiyarov, I. M.; Bach, U.; Bachev, R.; Berdyugin, A.; Bttcher, M.; Buemi, C. S.; Calcidese, P.; Carosati, D.; Charlot, P.; Chen, W.-P.; di Paola, A.; Dolci, M.; Dogru, S.; Doroshenko, V. T.; Efimov, Yu. S.; Erdem, A.; Frasca, A.; Fuhrmann, L.; Giommi, P.; Glowienka, L.; Gupta, A. C.; Gurwell, M. A.; Hagen-Thorn, V. A.; Hsiao, W.-S.; Ibrahimov, M. A.; Jordan, B.; Kamada, M.; Konstantinova, T. S.; Kopatskaya, E. N.; Kovalev, Y. Y.; Kovalev, Y. A.; Kurtanidze, O. M.; Lhteenmki, A.; Lanteri, L.; Larionova, L. V.; Leto, P.; Le Campion, P.; Lee, C.-U.; Lindfors, E.; Marilli, E.; McHardy, I.; Mingaliev, M. G.; Nazarov, S. V.; Nieppola, E.; Nilsson, K.; Ohlert, J.; Pasanen, M.; Porter, D.; Pursimo, T.; Ros, J. A.; Sadakane, K.; Sadun, A. C.; Sergeev, S. G.; Smith, N.; Strigachev, A.; Sumitomo, N.; Takalo, L. O.; Tanaka, K.; Trigilio, C.; Umana, G.; Ungerechts, H.; Volvach, A.; Yuan, W.

    2008-12-01

    Context: The quasar 3C 279 is among the most extreme blazars in terms of luminosity and variability of flux at all wavebands. Its variations in flux and polarization are quite complex and therefore require intensive monitoring observations at multiple wavebands to characterise and interpret the observed changes. Aims: In this paper, we present radio-to-optical data taken by the WEBT, supplemented by our VLBA and RXTE observations, of 3C 279. Our goal is to use this extensive database to draw inferences regarding the physics of the relativistic jet. Methods: We assemble multifrequency light curves with data from 30 ground-based observatories and the space-based instruments SWIFT (UVOT) and RXTE, along with linear polarization vs. time in the optical R band. In addition, we present a sequence of 22 images (with polarization vectors) at 43 GHz at resolution 0.15 milliarcsec, obtained with the VLBA. We analyse the light curves and polarization, as well as the spectral energy distributions at different epochs, corresponding to different brightness states. Results: We find that the IR-optical-UV continuum spectrum of the variable component corresponds to a power law with a constant slope of -1.6, while in the 2.4-10 keV X-ray band it varies in slope from -1.1 to -1.6. The steepest X-ray spectrum occurs at a flux minimum. During a decline in flux from maximum in late 2006, the optical and 43 GHz core polarization vectors rotate by ~300. Conclusions: The continuum spectrum agrees with steady injection of relativistic electrons with a power-law energy distribution of slope -3.2 that is steepened to -4.2 at high energies by radiative losses. The X-ray emission at flux minimum comes most likely from a new component that starts in an upstream section of the jet where inverse Compton scattering of seed photons from outside the jet is important. The rotation of the polarization vector implies that the jet contains a helical magnetic field that extends ~20 pc past the 43 GHz core. The radio-to-optical data presented in this paper are stored in the WEBT archive; for questions regarding their availability, please contact the WEBT president Massimo Villata (villata@oato.inaf.it).

  2. A Year of Hands-on Science: Exciting Theme Units with More Than 100 Activities, Projects, and Experiments To Make Science Come Alive.

    ERIC Educational Resources Information Center

    Kepler, Lynne; Novelli, Joan, Ed.

    This book contains 18 themed teaching units with 2 themes per chapter, organized seasonally around the traditional school year. Each theme includes natural connections and hands-on science activities that correspond to what children are already observing in their world. Each chapter begins with highlights of the month and a reproducible "Science

  3. Observation of Kilohertz Quasiperiodic Oscillations from the Atoll Source 4U 1702-429 by RXTE

    NASA Technical Reports Server (NTRS)

    Markwardt, C. B.; Strohmayer, Tod E.; Swank, Jean H.

    1998-01-01

    We present results of Rossi X-Ray Timing Explorer (RXTE) observations of the atoll source 4U 1702-429 in the middle of its luminosity range. Kilohertz-range quasiperiodic oscillations (QPOS) were observed first as a narrow (FWHM approximately 7 Hz) peak near 900 Hz, and later as a pair consisting of a narrow peak in the range 625 825 Hz and a faint broad (FWHM 91 Hz) peak. When the two peaks appeared simultaneously the separation was 333 +/- 5 Hz. Six type I thermonuclear bursts were detected, of which five exhibited almost coherent oscillations near 330 Hz, which makes 4U 1702-429 only the second source to show burst oscillations very close to the kilohertz QPO separation frequency. The energy spectrum and color-color diagram indicate that the source executed variations in the range between the "island" and "lower banana" atoll states. In addition to the kilohertz variability, oscillations at approximately 10, approximately 35, and 80 Hz were also detected at various times, superimposed on a red noise continuum. The centroid of the approximately 35 Hz QPO tracks the frequency of the kilohertz oscillation when they were both present. A Lense-Thirring gravitomagnetic precession interpretation appears more plausible in this case, compared to other atoll sources with low frequency QPOs.

  4. Monitoring the Black Hole Binary GRS 1758-258 with INTEGRAL and RXTE

    NASA Technical Reports Server (NTRS)

    Pottschmidt, Katja; Chernyakova, Masha; Lubinski, Piotr; Migliari, Simone; Smith, David M.; Zdziarski, Andrzej A.; Tomsick, John A.; Bezayiff, N.; Kreykenbohm, Ingo; Kretschmar, Peter; Kalemci, Emrah

    2008-01-01

    The microquasar GRS 1758-258 is one of only three persistent black hole binaries that spend most of their time in the hard spectral state, the other two being Cyg X-l and 1E 1741.7-2942. It therefore provides the rare opportunity for an extensive long term study of this important black hole state which is associated with strong variability and radio jet emission. INTEGRAL has been monitoring the source since the first Galactic Center Deep Exposure season in spring 2003 during two 2-3 months long Galactic Center viewing epochs each year, amounting to 11 epochs including spring of 2008. With the exception of the last epoch quasi-simultaneous RXTE monitoring observations are available as well. Here we present an analysis of the epoch averaged broad band spectra which display considerable long term variability, most notably the occurrence of two soft/off states, extreme examples for the hysteretic behavior of black hole binaries. The hard source spectrum and long exposures allow us to extend the analysis for several epochs to approximately 800 keV using PICsIT data and address the question of the presence of a non-thermal Comptonization component.

  5. Analysis of systematic errors of the ASM/RXTE monitor and GT-48 ?-ray telescope

    NASA Astrophysics Data System (ADS)

    Fidelis, V. V.

    2011-06-01

    The observational data concerning variations of light curves of supernovae remnantsthe Crab Nebula, Cassiopeia A, Tycho Brahe, and pulsar Velaover 14 days scale that may be attributed to systematic errors of the ASM/RXTE monitor are presented. The experimental systematic errors of the GT-48 ?-ray telescope in the mono mode of operation were also determined. For this the observational data of TeV J2032 + 4130 (Cyg ?-2, according to the Crimean version) were used and the stationary nature of its ?-ray emission was confirmed by long-term observations performed with HEGRA and MAGIC. The results of research allow us to draw the following conclusions: (1) light curves of supernovae remnants averaged for long observing periods have false statistically significant flux variations, (2) the level of systematic errors is proportional to the registered flux and decreases with increasing temporal scale of averaging, (3) the light curves of sources may be modulated by the year period, and (4) the systematic errors of the GT-48 ?-ray telescope, in the amount caused by observations in the mono mode and data processing with the stereo-algorithm come to 0.12 min-1.

  6. An Empirical Method for Improving the Quality of RXTE PCA Spectra

    NASA Astrophysics Data System (ADS)

    Garca, Javier A.; McClintock, Jeffrey E.; Steiner, James F.; Remillard, Ronald A.; Grinberg, Victoria

    2014-10-01

    We fitted all of the several hundred RXTE PCA spectra of the Crab individually to a simple power-law model; the total number of counts in the composite spectrum is >109. We then used the spectrum of residuals to derive a calibration tool, called pcacorr, that we apply to large samples of spectra for GX 339-4, H1743-322, and XTE J1550-564. Application of the tool improved the quality of all the fits, and the improvement is dramatic for spectra with >~ 107 counts. The Crab residual spectrum is somewhat different for each of the five Proportional Counter Array (PCA) detectors, but it was relatively stable over the course of the mission. We recommend that pcacorr be routinely applied to spectra with >~ 106 counts and that one include a systematic error of 0.1%, rather than the 0.5-1% value that has customarily been used. We expect that application of the tool will result in an increase in sensitivity of the PCA to faint spectral features by up to an order of magnitude.

  7. An empirical method for improving the quality of RXTE PCA spectra

    SciTech Connect

    García, Javier A.; McClintock, Jeffrey E.; Steiner, James F.; Remillard, Ronald A.; Grinberg, Victoria E-mail: jem@cfa.harvard.edu E-mail: rr@space.mit.edu

    2014-10-10

    We fitted all of the several hundred RXTE PCA spectra of the Crab individually to a simple power-law model; the total number of counts in the composite spectrum is >10{sup 9}. We then used the spectrum of residuals to derive a calibration tool, called pcacorr, that we apply to large samples of spectra for GX 339-4, H1743-322, and XTE J1550-564. Application of the tool improved the quality of all the fits, and the improvement is dramatic for spectra with ≳ 10{sup 7} counts. The Crab residual spectrum is somewhat different for each of the five Proportional Counter Array (PCA) detectors, but it was relatively stable over the course of the mission. We recommend that pcacorr be routinely applied to spectra with ≳ 10{sup 6} counts and that one include a systematic error of 0.1%, rather than the 0.5-1% value that has customarily been used. We expect that application of the tool will result in an increase in sensitivity of the PCA to faint spectral features by up to an order of magnitude.

  8. Map, Excite, Jump, and Measure: An Outreach Activity That Utilizes Seismology to Engage Students in Technology, Science, Engineering, and Mathematics

    NASA Astrophysics Data System (ADS)

    van der Lee, S.; Tekverk, K.; Rooney, K.; Boxerman, J.

    2013-12-01

    We designed and will present a lesson plan to teach students STEM concepts through seismology. The plan addresses new generation science standards in the Framework for K-12 Science Education as well AAAS Benchmarks for Science Literacy. The plan can be executed at a facility with a seismometer in a research facility or university, on a field trip, but it can also be used in a school setting with a school seismometer. Within the lesson plan, the students first use technology to obtain earthquake location data and map them. Next, the students learn about the science of earthquakes, which is followed by an engineering activity in which the students design a hypothetical seismometer and interact with the actual seismometer and live data display. Lastly the students use mathematics to locate an earthquake through trilateration. The lesson plan has been fine-tuned through implementation with over 150 students from grades 3-12 from the Chicago area.

  9. Using Remote Sensing Technology, Web Casts, and Participation in a Valuable Research Project to Jazz Teachers and Excite Students About Science

    NASA Astrophysics Data System (ADS)

    Benko, T. M.; Czajkowski, K. P.; Struble, J.; Zhao, L.

    2002-12-01

    Scientific education of primary and secondary school children has become a topic of concern in Ohio and throughout the United States. So with that in mind, how do you get students excited about learning science? One route is to inform and jazz teachers about current technology! The University of Toledo has hosted three one-week, NASA and OhioView sponsored professional development institutes entitled, Observing Earth from Space, for teachers from grades K-12 during July 2000, 2001, and 2002. Sixty-seven teachers from the Upper Midwest and Kansas with Earth Science, Social Studies, and Physics backgrounds attended. Each participant acquired new ideas, plenty of educational materials, and posters of satellite imagery. The teachers received basic training in remote sensing, global positioning systems, digital elevation models, and weather observing techniques and learned about useful remote sensing applications. This instruction was conducted through: 1) presentations given by research scientists, 2) integration of the learned content into authentic, hands-on lesson plans, and 3) participation in a learning adventure, where their students collected real-time earth science data at their respective schools while university research scientists gathered corresponding satellite imagery. The students observations were submitted via a simple Web interface: www.remotesensing.utoledo.edu. One of the very exciting platforms used to communicate with the teachers and students throughout the school year were live Web Casts sponsored by NASA Glenn Research Center. The students data have successfully assisted in the validation of cloud/snow remote sensing algorithms, and next year the students observations will include various surface temperature readings. The participation in a cutting-edge technology workshop and in an important global climate change research project, applicable in the classroom, has added another worthwhile dimension to the learning process and career awareness for both the teachers and their students.

  10. 16 yr of RXTE monitoring of five anomalous X-ray pulsars

    SciTech Connect

    Dib, Rim; Kaspi, Victoria M. E-mail: vkaspi@physics.mcgill.ca

    2014-03-20

    We present a summary of the long-term evolution of various properties of the five non-transient anomalous X-ray pulsars (AXPs) 1E 1841045, RXS J170849.0400910, 1E 2259+586, 4U 0142+61, and 1E 1048.15937, regularly monitored with RXTE from 1996 to 2012. We focus on three properties of these sources: the evolution of the timing, pulsed flux, and pulse profile. We report several new timing anomalies and radiative events, including a putative anti-glitch seen in 1E 2259+586 in 2009, and a second epoch of very large spin-down rate fluctuations in 1E 1048.15937 following a large flux outburst. We compile the properties of the 11 glitches and 4 glitch candidates observed from these 5 AXPs between 1996 and 2012. Overall, these monitoring observations reveal several apparent patterns in the behavior of this sample of AXPs: large radiative changes in AXPs (including long-lived flux enhancements, short bursts, and pulse profile changes) are rare, occurring typically only every few years per source; large radiative changes are almost always accompanied by some form of timing anomaly, usually a spin-up glitch; only 20%-30% of timing anomalies are accompanied by any form of radiative change. We find that AXP radiative behavior at the times of radiatively loud glitches is sufficiently similar to suggest common physical origins. The similarity in glitch properties when comparing radiatively loud and radiatively silent glitches in AXPs suggests a common physical origin in the stellar interior. Finally, the overall similarity of AXP and radio pulsar glitches suggests a common physical origin for both phenomena.

  11. RXTE Observations of the Seyfert 2 Galaxy MrK 348

    NASA Technical Reports Server (NTRS)

    Smith, David A.; Georgantopoulos, Ioannis; Warwick, Robert S.

    2000-01-01

    We present RXTE monitoring observations of the Seyfert 2 galaxy Mrk 348 spanning a 6 month period. The time-averaged spectrum in the 3-20 keV band shows many features characteristic of a Compton-thin Seyfert 2 galaxy, namely a hard underlying power-law continuum (Gamma approximately equal 1.8) with heavy soft X-ray absorption (N(sub H) approximately 10(exp 23)/sq cm) plus measurable iron K.alpha emission (equivalent width approximately 100 eV) and, at high energy, evidence for a reflection component (R approximately < 1). During the first half of the monitoring period the X-ray continuum flux from Mrk 348 remained relatively steady. However this was followed by a significant brightening of the source (by roughly a factor of 4) with the fastest change corresponding to a doubling of its X-ray flux on a timescale of about 20 days. The flux increase was accompanied by a marked softening of X-ray spectrum most likely attributable to a factor approximately 3 decline in the intrinsic line-of-sight column density. In contrast the iron K.alpha line and the reflection components showed no evidence of variability. These observations suggest a scenario in which the central X-ray source is surrounded by a patchy distribution of absorbing material located within about a light-week of the nucleus of Mrk 348. The random movement of individual clouds within the absorbing screen, across our line of sight, produces substantial temporal variations in the measured column density on timescales of weeks to months and gives rise to the observed X-ray spectral variability. However, as viewed from the nucleus the global coverage and typical thickness of the cloud layer remains relatively constant.

  12. An Expanded RXTE Survey of Long-Term X-ray Variability in Seyfert 1 Galaxies

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Edelson, R.

    2004-01-01

    The first seven years of RXTE monitoring of Seyfert 1 active galactic nuclei have been systematically analyzed to yield five homogenous samples of 2-12 keV light curves, probing hard X-ray variability on successively longer durations from approx. 1 day to approx. 3.5 years. 2-10 keV variability on time scales of approx. 1 day, as probed by ASCA, are included. All sources exhibit stronger X-ray variability towards longer time scales, with variability amplitudes saturating at the longest time scales, but the increase is greater for relatively higher luminosity sources. The well-documented anticorrelation between variability amplitude and luminosity is confirmed on all time scales. However, anticorrelations between variability amplitude and black hole mass estimate are evident on only the shortest time scales probed. The data are consistent with the models of power spectral density (PSD) movement described in Markowitz et al. (2003) and McHardy et al. (2004), whereby Seyfert 1 galaxies variability can be described by a single, universal PSD shape whose cutoff frequency scales with black hole mass. The best-fitting scaling relations between variability time scale, black hole mass and X-ray luminosity support an average accretion rate of 2% of the Eddington limit for the sample. Nearly all sources exhibit stronger variability in the relatively soft 2-4 keV band compared to the 7-12 keV band on all time scales. Color-flux diagrams support also Seyfert 1s' softening as they brighten. There are indications that relatively less luminous or less massive sources exhibit a greater degree of spectral variability for a given increase in overall flux.

  13. Twelve and a Half Years of Observations of Centaurus A with RXTE

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.; Markowitz, A.; Rivers, L.; Suchy, S.; Pottschmidt, K.; Kadler, M.; Mueller, C.; Wilms, J.

    2011-01-01

    The Rossi X-ray Timing Explorer has observed the nearest radio galaxy, Centaurus A, in 13 intervals from 1996 August to 2009 February over the 3 - 200 keV band. Spectra accumulated over the 13 intervals were well described with an absorbed power law and an iron line. Cut-off power laws and Compton reflection from cold matter did not provide a better description. For the 2009 January observation we set a lower limit on the cutoff energy at over 2 MeV. The power spectral density function was generated from RXTE/ASM and PCA data as well as an XMM-Newton long look, and clear evidence for a break at 18(+18/-7) days (68% conf.) was seen. Given Cen A's high black hole mass and very low value of L(sub x)/L(sub Edd), the break was a factor of 17+/-9 times higher than the break frequency predicted by the McHardy and coworkers relation, which was empirically derived for a sample of objects, which are radio-quiet and accreting at relatively high values of L(sub bol)/L(sub Edd). We have interpreted our observations in the context of a clumpy molecular torus. The variability characteristics and the broadband spectral energy distribution, when compared to Seyferts, imply that the bright hard X-ray continuum emission may originate at the base of the jet, yet from behind the absorbing line of sight material, in contrast to what is commonly observed from blazars.

  14. INTEGRAL and RXTE/ASM Observations on IGR J17098-3628

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Peng; Zhang, Shu; Schurch, Nick; Wang, Jian-Min; Collmar, Werner; Li, Ti-Pei; Qu, Jin-Lu; Zhang, Cheng-Min

    2008-10-01

    To further probe the possible nature of the unidentified source IGR J17098-3628, we have carried out a detailed analysis of its long-term time variability, as monitored by Rossi X-ray Timing Explorer/All Sky Monitor (RXTE/ASM), and of its hard X-ray properties, as observed by the International Gamma-Ray Astrophysics Laboratory (INTEGRAL). INTEGRAL has monitored this sky region for years, and significantly detected IGR J17098-3628 only when the source was in its dubbed active state. In particular, at ?20keV, Imager on Board of the INTEGRAL Satellite/INTEGRAL Soft Gamma-Ray Imager (IBIS/ISGRI) caught an outburst in 2005 March, lasting for 5 d with a detection significance of 73? (20--40 keV) and with emission at <200 keV. ASM observations have revealed that the outburst of the soft X-ray lightcurve is similar to that detected by INTEGRAL; however the peak of the soft X-ray lightcurve lags behind, or is preceded by, the hard X-ray (>20 keV) outburst by 2 d. This resembles the behavior of X-ray novae like XN 1124-683, and hence further suggests a Low-Mass X-ray Binary (LMXB) nature for IGR J17098-3628. While the quality of the ASM data prevents us from drawing any definite conclusions, these discoveries are important clues that, coupled with future observations, will help us to resolve the nature of IGR J17098-3628 that is unknown so far.

  15. How to Use a Bed of Nails to Facilitate Excitement during a Science Road Show Presentation at Local Schools

    NASA Astrophysics Data System (ADS)

    Pena, Fabian; Kridler, Shawn; Berger, Pete

    2008-03-01

    The authors will demonstrate how to use a bed of nails to pump up the students at local K-12 schools. The use during Science Road Show presentations will be addressed along with suggestions on how to build the drama and introduce humor and learning.

  16. Using Modern And Inexpensive Tools In the Classroom To Teach Spectroscopy And To Do Exciting Citizen Science On Astronomical Objects

    NASA Astrophysics Data System (ADS)

    Field, T.

    2014-12-01

    Spectroscopy is a key tool used in modern astronomical research. But, it's always been a difficult topic to teach or practice because the expense and complexity of the available tools. Over the past few years, there's been somewhat of a revolution in this field as new technologies have applied. In this presentation we'll review some new spectroscopy tools that enable educators, students and citizen scientists to do exciting spectroscopic work. With the addition of a simple, inexpensive grating, it's now possible to capture scientifically significant spectra of astronomical objects with small (6") telescopes and even just a DSLR. See the tools that citizen scientists are using to contribute data to pro-am collaborations around the world. We'll also examine a simple, surprisingly inexpensive, tripod-mounted spectrometer that can be used in the classroom for demonstrations and hands-on labs with gas tubes and other light sources. Both of the above instruments use a software program named RSpec, which is state of the art software suite that is easy to learn and easy to use. In this presentation we'll see these devices in operation and discuss how they can be used by educators to dramatically improve their teaching of this topic. You'll see how these tools can eliminate the frustration of hand-held rainbow foil and plastic spectrometers. And we'll review some exciting examples of astronomical spectra being collected by amateurs and educators.

  17. A Year of Hands-on Science: Exciting Theme Units with More Than 100 Activities, Projects, and Experiments To Make Science Come Alive.

    ERIC Educational Resources Information Center

    Kepler, Lynne; Novelli, Joan, Ed.

    This book contains 18 themed teaching units with 2 themes per chapter, organized seasonally around the traditional school year. Each theme includes natural connections and hands-on science activities that correspond to what children are already observing in their world. Each chapter begins with highlights of the month and a reproducible "Science…

  18. RXTE Observation of 4U 1630-47 During its 1998 Outburst

    NASA Technical Reports Server (NTRS)

    Dieters, Stefan W.

    1999-01-01

    During the 1998 outburst of 4U 1630-47 it was extensively observed with the Rossi X-ray Timing Explorer (RXTE). In order to cover the outburst more thoroughly our data (Obs. ID: 30178-0[1-2]- ) were combined with those of Cui et al. (Obs. ID: 30188-02-). These observations were later compared with the complementary observations. Power density and energy spectra have been made for each observation. The data was used to place radio and hard X-ray observations within context. Analysis of SAX (Satellite per Astronomia a raggi X) and BATSE (Burst and Transient Source Experiment) data was also included within the study. The count rate and position in hardness-intensity, color-color diagrams and simple spectral fits are used to track the concurrent spectral changes. The source showed seven distinct types of timing behavior, most of which show differences with the canonical black hole spectral/timing states. In marked contrast to previous outbursts, we find quasi-periodic oscillation (QPO) signals during nearly all stages of the outburst with frequencies between 0.06 Hz and 14 Hz and a remarkable variety of other characteristics. In particular we find large (up to 23% rms) amplitude QPO on the early rise. Later, slow 0.1 Hz semi- regular short (- 5 sec), 9 to 16% deep dips dominate the light curve. At this time there are two QPOS, one stable near 13.5 Hz and the other whose frequency drops from 6-8 Hz to - 4.5 Hz during the dips. BeppoSAX observations during the very late declining phase show 4U 1630-47 in a low state. These results will shortly be published. We are completing a detailed analysis of the energy spectra (in preparation). The QPO/noise properties are being correlated with the concurrent spectral changes. Detailed studies of the QPO are being undertaken using sophisticated timing analysis methods. Finally a comparison with the other outbursts of 1630-47 is being made.

  19. Chandra and RXTE Observations of 1E 1547.0-5408: Comparing the 2008 and 2009 Outbursts

    NASA Technical Reports Server (NTRS)

    Ng, C.-Y.; Kaspi, V. M.; Dib, R.; Olausen, S. A.; Scholz, P.; Guever, T.; Oezel, F.; Gavril, F. P.; Woods, P. M.

    2010-01-01

    We present results from observations of the magnetar 1E 1547.0-5408 (SGR J1550-5418) taken with the Chandra X-ray Observatory and the Rossi X-ray Timing Explorer (RXTE) following the source s outbursts in 2008 October and 2009 January. During the time span of the Chandra observations, which covers days 4 through 23 and days 2 through 16 after the 2008 and 2009 events, respectively, the source spectral shape over the Chandraband remained stable, while the pulsar s spindown rate in the same span in 2008 increased by a factor of 2.2 as measured by RXTE. This suggests decoupling between the source s spin-down and radiative changes, hence between the spin-down-inferred magnetic field strength and that inferred spectrally. The lack of spectral variation during flux decay is surprising for models of magnetar outbursts. We also found a strong anti-correlation between the phase-averaged flux and the pulsed fraction in the 2008 and 2009 Chandra data, but not in the pre-2008 measurements. We discuss these results in the context of the magnetar model.

  20. RXTE observations of the 1A 1118-61 in an outburst, and the discovery of a cyclotron line

    NASA Astrophysics Data System (ADS)

    Doroshenko, V.; Suchy, S.; Santangelo, A.; Staubert, R.; Kreykenbohm, I.; Rothschild, R.; Pottschmidt, K.; Wilms, J.

    2010-06-01

    We present the analysis of RXTE monitoring data obtained during the 2009 January outburst of the hard X-ray transient 1A 1118-61. Using these observations the broadband (3.5-120 keV) spectrum of the source was measured for the first time ever. We have found that the broadband continuum spectrum of the source is similar to other accreting pulsars and is well described by several conventionally used phenomenological models. We have discovered that regardless of the applied continuum model, a prominent broad absorption feature at ~55 keV is observed. We interpret this feature as a cyclotron resonance scattering feature (CRSF). The observed CRSF energy is one of the highest known and corresponds to a magnetic field of B ~ 4.8 1012 G in the scattering region. Our data also indicate the presence of an iron emission line presence that has not been previously reported for 1A 1118-61. Timing properties of the source, including a strong spin-up, were found to be similar to those observed by CGRO/BATSE during the previous outburst, but the broadband capabilities of RXTE reveal a more complicated energy dependency of the pulse-profile.

  1. RXTE Observations of the 1A 1118-61 in an Outburst, and the Discovery of a Cyclotron Line

    NASA Technical Reports Server (NTRS)

    Doroshenko, V.; Suchy, S.; Santangelo, A; Staubert, R.; Kreykenbohm, I.; Rothschild, R.; Pottschmidt, K.; Wilms, J.

    2010-01-01

    We present the analysis of RXTE monitoring data obtained during the January 2009 outburst of the hard X-ray transient IA 1118-61. Using these observations the broadband (3.5-120 keV) spectrum of the source was measured for the first time ever. We have found that the broadband continuum spectrum of the source is similar to other accreting pulsars and is well described by several conventionally used phenomenological models. We have discovered that regardless of the applied continuum model, a prominent broad absorption feature at approx. 55 keV is observed. We interpret this feature as a Cyclotron Resonance Scattering Feature (CRSF). The observed CRSF energy is one of the highest known and corresponds to a magnetic field of B approx. 4.8 x 10(exp 12) G in the scattering region. Furthermore, our data suggests an iron emission line presence, which was not reported previously for lA 1118-61 as well. Timing properties of the source, including a strong spin-up, were found to be similar to those observed by CGRO/BATSE during the previous outburst, however the broadband capabilities of RXTE reveal a more complicated energy dependency of the pulse-profile.

  2. Experience Gained From Launch and Early Orbit Support of the Rossi X-Ray Timing Explorer (RXTE)

    NASA Technical Reports Server (NTRS)

    Fink, D. R.; Chapman, K. B.; Davis, W. S.; Hashmall, J. A.; Shulman, S. E.; Underwood, S. C.; Zsoldos, J. M.; Harman, R. R.

    1996-01-01

    this paper reports the results to date of early mission support provided by the personnel of the Goddard Space Flight Center Flight Dynamics Division (FDD) for the Rossi X-Ray Timing Explorer (RXTE) spacecraft. For this mission, the FDD supports onboard attitude determination and ephemeris propagation by supplying ground-based orbit and attitude solutions and calibration results. The first phase of that support was to provide launch window analyses. As the launch window was determined, acquisition attitudes were calculated and calibration slews were planned. postlaunch, these slews provided the basis for ground determined calibration. Ground determined calibration results are used to improve the accuracy of onboard solutions. The FDD is applying new calibration tools designed to facilitate use of the simultaneous, high-accuracy star observations from the two RXTE star trackers for ground attitude determination and calibration. An evaluation of the performance of these tools is presented. The FDD provides updates to the onboard star catalog based on preflight analysis and analysis of flight data. The in-flight results of the mission support in each area are summarized and compared with pre-mission expectations.

  3. RXTE and BeppoSAX Observations of MCG-5-23-16: Reflection From Distant Cold Material

    NASA Technical Reports Server (NTRS)

    Mattson, B. J.; Weaver, K. A.

    2003-01-01

    We examine the spectral variability of the Seyfert 1.9 galaxy MCG-5-23-16 using RXTE and BeppoSAX observations spanning 2 years from April 1996 to April 1998. During the first year the X-ray source brightens by a factor of approximately 25% on timescales of days to months. During this time, the reprocessed continuum emission seen with RXTE does not respond measurably to the continuum increase. However, by the end of the second year during the BeppoSAX epoch the X-ray source has faded again. This time, the reprocessed emission has also faded, indicating that the reprocessed flux has responded to the continuum. If these effects are caused by time delays due to the distance between the X-ray source and the reprocessing region, we derive a light crossing time of between approximately 1 light day and approximately 1.5 light years. This corresponds to a distance of 0.001 pc to 0.55 pc, which implies that the reprocessed emission originates between 3 x 10(exp 15) cm and 1.6 x 10(exp l8) cm from the X-ray source. In other words, the reprocessing in MCG-5-23-16 is not dominated by the inner regions of a standard accretion disk.

  4. Cryogenic exciter

    DOEpatents

    Bray, James William; Garces, Luis Jose

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  5. International Observe the Moon Night - An Opportunity to Participate in the Year of the Solar System While Sharing the Excitement of Lunar Science and Exploration with the Public

    NASA Astrophysics Data System (ADS)

    Bleacher, L.; Daou, D.; Day, B. H.; Hsu, B. C.; Jones, A. P.; Mitchell, B.; Shaner, A. J.; Shipp, S. S.

    2010-12-01

    International Observe the Moon Night (InOMN) is a multi-nation effort to share the excitement of recent lunar missions and new science results with education communities, amateur astronomers, space enthusiasts, and the general public. It is also intended to encourage the world to experience the thrill of observing Earth’s closest neighbor. The inaugural InOMN took place on September 18, 2010. People in over 26 countries gathered together in groups big and small to learn about the Moon through presentations by scientists, astronomers, and engineers; participate in hands-on activities; and observe the Moon through telescopes, binoculars, and the naked eye. Next year’s InOMN will take place on October 8, 2011 during the Year of the Solar System (YSS). The October 2011 YSS theme will be “Moons/Rings Across the Solar System.” InOMN is perfectly suited as an event that any museum, science center, planetarium, university, school, or other group can implement to celebrate YSS. The InOMN Coordinating Committee has developed a variety of resources and materials to make it easy to host an InOMN event of any size. Interested groups are encouraged to utilize the InOMN website (observethemoonnight.org) in planning their InOMN event for 2011/YSS. The website contains links to Moon resources, educational activities, suggestions for hosting an event, free downloads of logos and flyers for advertising an event, and contests. New for 2011 will be a discussion forum for event hosts to share their plans, tips, and experiences. Together, YSS and InOMN will enable the public to maintain its curiosity about the Moon and to gain a better understanding of the Moon’s formation, evolution, and place in the night sky.

  6. Food Science.

    ERIC Educational Resources Information Center

    Barkman, Susan J.

    1996-01-01

    Presents food science experiments designed for high school science classes that aim at getting students excited about science and providing them with real-life applications. Enables students to see the application of chemistry, microbiology, engineering, and other basic and applied sciences to the production, processing, preservation, evaluation,

  7. Food Science.

    ERIC Educational Resources Information Center

    Barkman, Susan J.

    1996-01-01

    Presents food science experiments designed for high school science classes that aim at getting students excited about science and providing them with real-life applications. Enables students to see the application of chemistry, microbiology, engineering, and other basic and applied sciences to the production, processing, preservation, evaluation,…

  8. Science.

    ERIC Educational Resources Information Center

    Whitman, Betsy Blizard

    1994-01-01

    Presents a group of 21 innovative science activities from teachers nationwide designed to sharpen elementary students knowledge of science. The article is part of a package of 100 creative ideas for keeping elementary students enthused about learning in language arts, science, social studies, and math. (SM)

  9. The Nature of the X-Ray Binary IGR J19294+1816 from INTEGRAL, RXTE, and Swift Observations

    NASA Technical Reports Server (NTRS)

    Rodriquez, J.; Tomsick, J. A.; Bodaghee, A.; ZuritaHeras, J.-A.; Chaty, S.; Paizis, A.; Corbel, S.

    2009-01-01

    We report the results of a high-energy multi-instrumental campaign with INTEGRAL, RXTE, and Swift of the recently discovered INTEGRAL source IGR J19294+ 1816. The Swift/XRT data allow us to refine the position of the source to R.A. (J2000) = 19h 29m 55.9s, Decl. (J2000) = +18 deg 18 feet 38 inches . 4 (+/- 3 inches .5), which in turn permits us to identify a candidate infrared counterpart. The Swift and RXTE spectra are well fitted with absorbed power laws with hard (Gamma approx 1) photon indices. During the longest Swift observation, we obtained evidence of absorption in true excess to the Galactic value, which may indicate some intrinsic absorption in this source. We detected a strong (P = 40%) pulsations at 12.43781 (+/- 0.00003) s that we interpret as the spin period of a pulsar. All these results, coupled with the possible 117 day orbital period, point to IGR J19294+ 1816 being an high-mass X-ray binary (HMXB) with a Be companion star. However, while the long-term INTEGRAL/IBIS/ISGRI 18-40 keV light curve shows that the source spends most of its time in an undetectable state, we detect occurrences of short (2000-3000 s) and intense flares that are more typical of supergiant fast X-ray transients. We therefore cannot make firm conclusions on the type of system, and we discuss the possible implication of IGR J19294+1816 being an Supergiant Fast X-ray Transient (SFXT).

  10. Comprehensive Analysis of RXTE Data from Cyg X-1. Spectral Index-Quasi-Periodic Oscillation Frequency-Luminosity Correlations

    NASA Technical Reports Server (NTRS)

    Shaposhnikov, Nickolai; Titarchuk, Lev

    2006-01-01

    We present timing and spectral analysis of approx. 2.2 Ms of Rossi X-ray Time Explorer (RXTE) archival data from Cyg X-1. Using the generic Comptonization model we reveal that the spectrum of Cyg X-1 consists of three components: a thermal seed photon spectrum, a Comptonized part of the seed photon spectrum and the iron line. We find a strong correlation between 0.1-20 Hz frequencies of quasiperiodic oscillations (QPOs) and the spectral power-law index. Presence of two spectral phases (states) are clearly seen in the data when the spectral indices saturate at low and high values of QPO frequencies. This saturation effect was discovered earlier in a number of black hole candidate (BHC) sources and now we strongly confirm this phenomenon in Cyg X-1. In the soft state this index- QPO frequency correlation shows a saturation of the photon index Gamma approx. 2.1 at high values of the low frequency upsilon(sub L). The saturation level of Gamma approx. 2.1 is the lowest value found yet in BHCs. The bolometric luminosity does not show clear correlation with the index. We also show that Fe K(sub alpha) emission line strength (equivalent width, EW) correlates with the QPO frequency. EW increases from 200 eV in the low/hard state to 1.5 keV in the high/soft state. The revealed observational correlations allow us to propose a scenario for the spectral transition and iron line formation which occur in BHC sources. We also present the spectral state (the power-law index) evolution for eight years of Cyg X-1 observations by RXTE.

  11. Science.

    ERIC Educational Resources Information Center

    Roach, Linda E., Ed.

    This document contains the following papers on science instruction and technology: "A 3-D Journey in Space: A New Visual Cognitive Adventure" (Yoav Yair, Rachel Mintz, and Shai Litvak); "Using Collaborative Inquiry and Interactive Technologies in an Environmental Science Project for Middle School Teachers: A Description and Analysis" (Patricia…

  12. Structure of the Circumnuclear Region of Seyfert 2 Galaxies Revealed by RXTE Hard X-Ray Observations of NGC 4945

    NASA Technical Reports Server (NTRS)

    Madejski, G.; Zycki, P.; Done, C.; Valinia, A.; Blanco, P.; Rothschild, R.; Turek, B.

    2000-01-01

    NGC 4945 is one of the brightest Se.yfert galaxies on the sky at 100 keV, but is completely absorbed below 10 keV, implying an optical depth of the absorber to electron scattering of a few; its absorption column is probably the largest which still allows a direct view of the nucleus at hard X-ray energies. Our observations of it with the Rossi X-ray Timing Explorer (RXTE) satellite confirm the large absorption, which for a simple phenomenological fit using an absorber with Solar abundances implies a column of 4.5(sup 0.4, sub -0.4) x 10(exp 24) /sq cm. Using a a more realistic scenario (requiring Monte Carlo modeling of the scattering), we infer the optical depth to Thomson scattering of approximately 2.4. If such a scattering medium were to subtend a large solid angle from the nucleus, it should smear out any intrinsic hard X-ray variability on time scales shorter than the light travel time through it. The rapid (with a time scale of approximately a day) hard X-ray variability of NGC 4945 we observed with the RXTE implies that the bulk of the extreme absorption in this object does not originate in a parsec-size, geometrically thick molecular torus. Limits on the amount of scattered flux require that the optically thick material on parsec scales must be rather geometrically thin, subtending a half-angle < 10 deg. This is only marginally consistent with the recent determinations of the obscuring column in hard X-rays, where only a quarter of Seyfert 2s have columns which are optically thick, and presents a problem in accounting for the Cosmic X-ray Background primarily with AGN possessing the geometry as that inferred by us. The small solid angle of the obscuring material, together with the black hole mass (of approximately 1.4 x 10(exp 6) solar mass) from megamaser measurements. allows a robust determination of the source luminosity, which in turn implies that the source radiates at approximately 10% of the Eddington limit.

  13. RXTE Timing and Spectroscopy of a Black Hole X-Ray Binary in Outburst

    NASA Technical Reports Server (NTRS)

    Miller, Jon M.

    2004-01-01

    This program was executed primarily to observe the black hole transient GX339-4. Observations were made simultaneously with XMM-Newton in 2004 March, and observations simultaneous with Chandra will continue to be made in the fall of 2004. As the total data set has not yet been obtained, a great deal of work remains. Preliminary examination of the data has shown extremely exciting spectral features (Fe K-alpha emission lines) and timing features (strong QPOs and flaring variability) of exactly the sort we hoped to obtain. We expect that the results of these observations will be finalized over the next year. The results will be presented in 2-3 publications in refereed journals. We have requested a no-cost extension of this grant to analyze and report our findings.

  14. The 2009 outburst of accretion-powered millisecond pulsar IGR J17511-3057 as observed by Swift and RXTE

    NASA Astrophysics Data System (ADS)

    Ibragimov, Askar; Poutanen, Juri; Kajava, Jari

    Accretion-powered millisecond pulsars (AMPs) are very interesting astrophysical objects. Mat-ter from accretion disk is captured by star's magnetic field and falls along the field lines, creating "hotspots" near magnetic poles of the star. Typical spectrum of an AMP contains a disk emis-sion, blackbody emission of a hotspot and a powerlaw tail, produced by thermal Comptonizaion in accreting shock. Pulse profiles of these sources are modified by relativistic effects and can be used to put geometrical constraints and to understand physical processes near the compact object. IGR J17511-3057 was discovered on September 12, 2009 during the INTEGRAL Galactic Bulge monitoring program. The source has the pulse frequency of 245 Hz. In this work, we study spectral and temporal characheristics of IGR J17511-3057 during the outburst, based on Swift and RXTE data. We analyze its energy spectra in range 0.6-150 keV, phase-resolved spectra, pulse profiles, time lags and discuss physical conditions in the source.

  15. RXTE, VLBA, Optical, and Radio Monitoring of the Quasars 3C 279, PKS 1510--089, and 3C 273

    NASA Technical Reports Server (NTRS)

    Marscher, A. P.; Jorstad, S. G.; Aller, M. F.; McHardy, I. M.; Balonek, T. J.

    2001-01-01

    We are continuing our combined RXTE X-ray, VLBA imaging (at 43 GHz), optical (several observatories), and radio (University of Michigan Radio Astronomy Observatory) monitoring of the quasars 3C 279 and PKS 1510-089, and have started similar monitoring of 3C 273. X-ray flares in 3C 279 and PKS 1510-089 are associated with ejections of superluminal components. In addition, there is a close connection between the optical and X-ray variability of 3C 279. There is a strong correlation between the 14.5 GHz and X-ray variability of PKS 1510-089 in 1997 and 1998 (with the radio leading the X-ray) that becomes weaker in subsequent years. X-ray fluctuations occur on a variety of timescales in 3C 273, with a major prolonged outburst in mid-2001. The lead author will discuss the correlations in terms of inverse Compton models for the X-ray emission coupled with synchrotron models for the lower-frequency radiation. Synchrotron self-Compton models can explain the "reverse" time lag in PKS 1510-089 is well as the variable correlation between the X-ray variations and those at lower frequencies in this object and in 3C 279.

  16. Monitoring the Violent Activity from the Inner Accretion Disk of the Seyfert 1.9 Galaxy NGC 2992 with RXTE

    NASA Technical Reports Server (NTRS)

    Mruphy, Kendrah D.; Yaqoob, Tahir; Terashima, Yuichi

    2007-01-01

    We present the results of a one year monitoring campaign of the Seyfert 1.9 galaxy NGC 2992 with RXTE. Historically, the source has been shown to vary dramatically in 2-10 keV flux over timescales of years and was thought to be slowly transitioning between periods of quiescence and active accretion. Our results show that in one year the source continuum flux covered almost the entire historical range, making it unlikely that the low-luminosity states correspond to the accretion mechanism switching off. During flaring episodes we found that a highly redshifted Fe K line appears, implying that the violent activity is occurring in the inner accretion disk, within 100 gravitational radii of the central black hole. We also found that the Compton y parameter for the X-ray continuum remained approximately constant during the large amplitude variability. These observations make NGC 2992 well-suited for future multi-waveband monitoring, as a test-bed for constraining accretion models.

  17. RXTE-PCA observations of 1A 1118-61: timing and spectral studies during an outburst

    NASA Astrophysics Data System (ADS)

    Devasia, Jincy; James, Marykutty; Paul, Biswajit; Indulekha, Kavila

    2011-06-01

    We report a detailed timing and spectral analysis of Rossi X-ray Timing Explorer Proportional Counter Array (RXTE-PCA) data obtained from observations during the outburst of a transient X-ray pulsar 1A 1118-61 in 2009 January. The pulse profile showed significant evolution during the outburst and also significant energy dependence - a double-peaked profile up to 10 keV and a single peak at higher energy. We have also detected quasi-periodic oscillations (QPOs) at 0.07-0.09 Hz. The rms value of the QPO is 5.2 per cent, and it shows a significant energy dependence with highest rms of 7 per cent at 9 keV. The QPO frequency changed from 0.09 to 0.07 Hz within 10 d. The magnetic field strength calculated using the QPO frequency and the X-ray luminosity is in agreement with the magnetic field strength measured from the energy of the cyclotron absorption feature detected in this source. The 3-30 keV energy spectrum over the 2009 outburst of 1A 1118-61 can be well fitted with a partial covering power-law model with a high-energy cut-off and an iron fluorescence line emission. The pulse phase resolved spectral analysis shows that the partial covering and high-energy cut-off model parameters have significant changes with the pulse phase.

  18. SWIFT AND RXTE OBSERVATIONS OF THE BLACK HOLE TRANSIENT GX 339-4 IN THE HARD STATE BETWEEN OUTBURSTS

    SciTech Connect

    Allured, Ryan; Tomsick, John A.; Kaaret, Philip; Yamaoka, Kazutaka E-mail: jtomsick@ssl.berkeley.edu E-mail: yamaoka@stelab.nagoya-u.ac.jp

    2013-09-10

    We use simultaneous Swift and RXTE observations of the black hole binary GX 339-4 to measure the inner radius of its accretion disk in the hard state down to 0.4% L{sub Edd} via modeling of the thermal disk emission and the relativistically broadened iron line. For the luminosity range covered in this work, our results rule out a significantly truncated disk at 100-1000 R{sub g} as predicted by the advection-dominated accretion flow paradigm. The measurements depend strongly on the assumed emission geometry, with most results providing no clear picture of radius evolution. If the inclination is constrained to roughly 20 Degree-Sign , however, the measurements based on the thermal disk emission suggest a mildly receding disk at a luminosity of 0.4% L{sub Edd}. The iron abundance varies between {approx}1 and 2 solar abundances, with the i = 20 Degree-Sign results indicating a negative correlation with luminosity, though this is likely due to a change in disk illumination geometry.

  19. X-Ray Outbursts of Low-mass X-Ray Binary Transients Observed in the RXTE Era

    NASA Astrophysics Data System (ADS)

    Yan, Zhen; Yu, Wenfei

    2015-06-01

    We have performed a statistical study of the properties of 110 bright X-ray outbursts in 36 low-mass X-ray binary transients (LMXBTs) seen with the All-Sky Monitor (2-12 keV) on board the Rossi X-ray Timing Explorer (RXTE) in 1996-2011. We have measured a number of outburst properties, including peak X-ray luminosity, rate of change of luminosity on a daily timescale, e-folding rise and decay timescales, outburst duration, and total radiated energy. We found that the average properties, such as peak X-ray luminosity, rise and decay timescales, outburst duration, and total radiated energy of black hole LMXBTs, are at least two times larger than those of neutron star LMXBTs, implying that the measurements of these properties may provide preliminary clues to the nature of the compact object of a newly discovered LMXBT. We also found that the outburst peak X-ray luminosity is correlated with the rate of change of X-ray luminosity in both the rise and decay phases, which is consistent with our previous studies. Positive correlations between total radiated energy and peak X-ray luminosity, and between total radiated energy and the e-folding rise or decay timescale, are also found in the outbursts. These correlations suggest that the mass stored in the disk before an outburst is the primary initial condition that sets up the outburst properties seen later. We also found that the outbursts of two transient stellar-mass ultraluminous X-ray sources in M31 also roughly follow the correlations, which indicate that the same outburst mechanism works for the brighter outbursts of these two sources in M31 that reached the Eddington luminosity.

  20. Statistical Properties of Local AGNs Inferred from the RXTE 3-20 keV All-Sky Survey

    NASA Astrophysics Data System (ADS)

    Revnivtsev, M.; Sazonov, S. Yu.

    We have recently ([1]) performed an all-sky survey in the 3-20 keV band from the data accumulated during satellite slews in 1996-2002 - the RXTE slew survey (XSS). For 90% of the sky at |b|>10 , a flux limit for source detection of 2.510-11 erg/s/sq.cm(3-20 keV) or lower was achieved, while a combined area of 7000 sq.deg was sampled to record flux levels (for such very large-area surveys) below 10-11 erg/s/sq.cm. A catalog contains 294 X-ray sources. 236 of these sources were identified with a single known astronomical object. Of particular interest are 100 identified active galactic nuclei (AGNs) and 35 unidentified sources. The hard spectra of the latter suggest that many of them will probably also prove AGNs when follow-up observations are performed. Most of the detected AGNs belong to the local population (z<0.1). In addition, the hard X-ray band of the XSS (3-20 keV) as compared to most previous X-ray surveys, performed at photon energies below 10 keV, has made possible the detection of a substantial number of X-ray absorbed AGNs (mostly Seyfert 2 galaxies). These properties make the XSS sample of AGNs a valuable one for the study of the local population of AGNs. We carried out a thorough statistical analysis of the above sample in order to investigate several key properties of the local population of AGNs, in particular their distribution in intrinsic absorption column density (NH) and X-ray luminosity function ([2]). Knowledge of these characteristics provides important constraints for AGN unification models and synthesis of the cosmic X-ray background, and is further needed to understand the details of the accretion-driven growth of supermassive black holes in the nuclei of galaxies.

  1. Excited Delirium

    PubMed Central

    Takeuchi, Asia; Ahern, Terence L.; Henderson, Sean O.

    2011-01-01

    Excited (or agitated) delirium is characterized by agitation, aggression, acute distress and sudden death, often in the pre-hospital care setting. It is typically associated with the use of drugs that alter dopamine processing, hyperthermia, and, most notably, sometimes with death of the affected person in the custody of law enforcement. Subjects typically die from cardiopulmonary arrest, although the cause is debated. Unfortunately an adequate treatment plan has yet to be established, in part due to the fact that most patients die before hospital arrival. While there is still much to be discovered about the pathophysiology and treatment, it is hoped that this extensive review will provide both police and medical personnel with the information necessary to recognize and respond appropriately to excited delirium. PMID:21691475

  2. Excited baryons

    SciTech Connect

    Mukhopadhyay, N.C.

    1986-01-01

    The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested. (LEW)

  3. Discovery and Monitoring of a New Black Hole Candidate XTE J1752-223 with RXTE: RMS Spectrum Evolution, BH Mass and the Source Distance

    NASA Technical Reports Server (NTRS)

    Shaposhinikov, Nikolai; Markwardt, Craig; Swank, Jean; Krimm, Hans

    2010-01-01

    We report on the discovery and monitoring observations of a new galactic black hole candidate XTE J1752-223 by Rossi X-ray Timing Explorer (RXTE). The new source appeared on the X-ray sky on October 21 2009 and was active for almost 8 months. Phenomenologically, the source exhibited the low-hard/highsoft spectral state bi-modality and the variability evolution during the state transition that matches standard behavior expected from a stellar mass black hole binary. We model the energy spectrum throughout the outburst using a generic Comptonization model assuming that part of the input soft radiation in the form of a black body spectrum gets reprocessed in the Comptonizing medium. We follow the evolution of fractional root-mean-square (RMS) variability in the RXTE/PCA energy band with the source spectral state and conclude that broad band variability is strongly correlated with the source hardness (or Comptonized fraction). We follow changes in the energy distribution of rms variability during the low-hard state and the state transition and find further evidence that variable emission is strongly concentrated in the power-law spectral component. We discuss the implication of our results to the Comptonization regimes during different spectral states. Correlations of spectral and variability properties provide measurements of the BH mass and distance to the source. The spectral-timing correlation scaling technique applied to the RXTE observations during the hardto- soft state transition indicates a mass of the BH in XTE J1752-223 between 8 and 11 solar masses and a distance to the source about 3.5 kiloparsec.

  4. Development of laser-excited molecular luminescence spectrometric methods for polycyclic aromatic hydrocarbons in environmental sciences: Final progress report, March 1, 1985 to February 28, 1989

    SciTech Connect

    Winefordner, J.D.

    1989-01-01

    Our research efforts have covered eight major areas, namely Room Temperature Phosphorimetry, Constant Energy Synchronous Luminescence Spectrometry, Laser Excited Fluorescence Spectrometry, Fingerprinting of Air Particulates, a unique Self-Cleaning Cooled Belt for Low Temperature Shpolskii Spectroscopy, Molecular Emission of Gases, FT Molecular Luminescence Spectrometry and Electronic Measurement Systems. These eight areas, which have resulted in 18 DOE supported publications (see listing at end), are summarized. 18 refs.

  5. RXTE All-Sky Slew Survey. Catalog of X-Ray Sources at B Greater Than 10 deg

    NASA Technical Reports Server (NTRS)

    Revnivtsev, M.; Sazonov, S.; Jahoda, K.; Gilfanov, M.

    2004-01-01

    We report results of a serendipitous hard X-ray (3-20 keV), nearly all-sky (absolute value of b greater than l0 deg.) survey based on RXTE/PCA observations performed during satellite reorientations in 1996-2002. The survey is 80% (90%) complete to a 4(sigma) limiting flux of approx. = 1.8 (2.5) x 10(exp -l1) erg/s sq cm in the 3-20 keV band. The achieved sensitivity in the 3-8 keV and 8-20 keV subbands is similar to and an order of magnitude higher than that of the previously record HEAO-1 A1 and HEAO-1 A4 all-sky surveys, respectively. A combined 7 x 10(exp 3) sq. deg area of the sky is sampled to flux levels below l0(exp -11) erg/ s sq cm (3-20 keV). In total 294 sources are detected and localized to better than 1 deg. 236 (80%) of these can be confidently associated with a known astrophysical object; another 22 likely result from the superposition of 2 or 3 closely located known sources. 35 detected sources remain unidentified, although for 12 of these we report a likely soft X-ray counterpart from the ROSAT all-sky survey bright source catalog. Of the reliably identified sources, 63 have local origin (Milky Way, LMC or SMC), 64 are clusters of galaxies and 100 are active galactic nuclei (AGN). The fact that the unidentified X-ray sources have hard spectra suggests that the majority of them are AGN, including highly obscured ones (N(sub H) greater than l0(exp 23)/sq cm). For the first time we present a log N-log S diagram for extragalactic sources above 4 x l0(exp -12) erg/ s sq cm at 8-20 keV. Key words. cosmo1ogy:observations - diffuse radiation - X-rays general

  6. Corona, Jet, and Relativistic Line Models for Suzaku/RXTE/Chandra-HETG Observations of the Cygnus X-1 Hard State

    NASA Technical Reports Server (NTRS)

    Nowak, Michael A.; Hanke, Manfred; Trowbridge, Sarah N.; Markoff, Sera B.; Wilms, Joern; Pottschmidt, Katja; Coppi, Paolo; Maitra, Dipankar; Davis, Jhn E.; Tramper, Frank

    2009-01-01

    Using Suzaku and the Rossi X-ray Timing Explorer (RXTE), we have conducted a series of four simultaneous observations of the galactic black hole candidate Cyg X-1 in what were historically faint and spectrally hard "low states". Additionally, all of these observations occurred near superior conjunction with our line of sight to the X-ray source passing through the dense phases of the "focused wind" from the mass donating secondary. One of our observations was also simultaneous with observations by the Chandra-High Energy Transmission Grating (HETG). These latter spectra are crucial for revealing the ionized absorption due to the secondary s focused wind. Such absorption is present and must be accounted for in all four spectra. These simultaneous data give an unprecedented view of the 0.8-300 keV spectrum of Cyg X-1, and hence bear upon both corona and X-ray emitting jet models of black hole hard states. Three models fit the spectra well: coronae with thermal or mixed thermal/non-thermal electron populations, and jets. All three models require a soft component that we fit with a low temperature disk spectrum with an inner radius of only a few tens of GM/c2. All three models also agree that the known spectral break at 10 keV is not solely due to the presence of reflection, but each gives a different underlying explanation for the augmentation of this break. Thus whereas all three models require that there is a relativistically broadened Fe line, the strength and inner radius of such a line is dependent upon the specific model, thus making premature line-based estimates of the black hole spin in the Cyg X-1 system. We look at the relativistic line in detail, accounting for the narrow Fe emission and ionized absorption detected by HETG. Although the specific relativistic parameters of the line are continuum-dependent, none of the broad line fits allow for an inner disk radius that is > 40 GM/c(sup 2).

  7. X-RAY PHASE-RESOLVED SPECTROSCOPY OF PSRs B0531+21, B1509-58, AND B0540-69 WITH RXTE

    SciTech Connect

    Ge, M. Y.; Lu, F. J.; Qu, J. L.; Zheng, S. J.; Chen, Y.; Han, D. W.

    2012-04-01

    The Rossi X-Ray Timing Explorer (RXTE) has made hundreds of observations on three famous young pulsars (PSRs) B0531+21 (Crab), B1509-58, and B0540-69. Using the archive RXTE data, we have studied the phase-resolved spectral properties of these pulsars in details. The variation of the X-ray spectrum with phase of PSR B0531+21 is confirmed here much more precisely and more details are revealed than in the previous studies: The spectrum softens from the beginning of the first pulse, turns to harden right at the pulse peak and becomes the hardest at the bottom of the bridge, softens gradually until the second peak, and then softens rapidly. Different from the previous studies, we found that the spectrum of PSR B1509-58 is significantly harder in the center of the pulse, which is also in contrast to that of PSR B0531+21. The variation of the X-ray spectrum of PSR B0540-69 seems similar to that of PSR B1509-58, but with a lower significance. Using about 10 years of data span, we also studied the real time evolution of the spectra of these pulsars, and no significant evolution has been detected. We discuss the constraints of these results on theoretical models of pulsar X-ray emission.

  8. Revisit to the RXTE and ASCA Data for GRO J1655-40: Effects of Radiative Transfer in Corona and Color Hardening in the Disk

    NASA Technical Reports Server (NTRS)

    Zhang, S. Nan; Zhang, Xiaoling; Wu, Xuebing; Yao, Yangsen; Sun, Xuejun; Xu, Haiguang; Cui, Wei; Chen, Wan; Harmon, B. A.; Robinson, C. R.

    1999-01-01

    The results of spectral modeling of the data for a series of RXTE observations and four ASCA observations of GRO J1655-40 are presented. The thermal Comptonization model is used instead of the power-law model for the hard component of the two-component continuum spectra. The previously reported dramatic variations of the apparent inner disk radius of GRO J1655-40 during its outburst may be due to the inverse Compton scattering in the hot corona. A procedure is developed for making the radiative transfer correction to the fitting parameters from RXTE data and a more stable inner disk radius is obtained. A practical process of determining the color correction (hardening) factor from observational data is proposed and applied to the four ASCA observations of GRO J1655-40. We found that the color correction factor may vary significantly between different observations and the finally corrected physical inner disk radius remains reasonably stable over a large range of luminosity and spectral states.

  9. Swift/BAT and RXTE Observations of the Peculiar X-ray Binary 4U 2206+54 - Disappearance of the 9.6 Day Modulation

    NASA Technical Reports Server (NTRS)

    Corbet, R. H. D.; Markwardt, C.; Tueller, J.

    2007-01-01

    Observations of the high-mass X-ray binary 4U 2206+54 with the Swift Burst Alert Telescope (BAT) do not show modulation at the previously reported period of 9.6 days found from observations made with the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM). Instead, the strongest peak in the power spectrum of the BAT light curve occurs at a period of 19.25+/-0.08 days, twice the period found with the RXTE ASM. The maximum of the folded BAT light curve is also delayed compared to the maximum of the folded ASM light curve. The most recent ASM data folded on twice the 9.6 day period show 'similar morphology to the folded BAT light curve. This suggests that the apparent period doubling is a recent secular change rather than an energy-dependent effect. The 9.6 day period is thus not a permanent strong feature of the light curve. We suggest that the orbital period of 4U 2206+54 may be twice the previously proposed value.

  10. RXTE Observation of Cygnus X-1: III. Implications for Compton Corona and ADAF Models. Report 3; Implications for Compton Corona and ADAF Models

    NASA Technical Reports Server (NTRS)

    Nowak, Michael A.; Wilms, Joern; Vaughan, Brian A.; Dove, James B.; Begelman, Mitchell C.

    1999-01-01

    We have recently shown that a 'sphere + disk' geometry Compton corona model provides a good description of Rossi X-ray Timing Explorer (RXTE) observations of the hard/low state of Cygnus X-1. Separately, we have analyzed the temporal data provided by RXTE. In this paper we consider the implications of this timing analysis for our best-fit 'sphere + disk' Comptonization models. We focus our attention on the observed Fourier frequency-dependent time delays between hard and soft photons. We consider whether the observed time delays are: created in the disk but are merely reprocessed by the corona; created by differences between the hard and soft photon diffusion times in coronae with extremely large radii; or are due to 'propagation' of disturbances through the corona. We find that the time delays are most likely created directly within the corona; however, it is currently uncertain which specific model is the most likely explanation. Models that posit a large coronal radius [or equivalently, a large Advection Dominated Accretion Flow (ADAF) region] do not fully address all the details of the observed spectrum. The Compton corona models that do address the full spectrum do not contain dynamical information. We show, however, that simple phenomenological propagation models for the observed time delays for these latter models imply extremely slow characteristic propagation speeds within the coronal region.

  11. Launch Excitement with Water Rockets

    ERIC Educational Resources Information Center

    Sanchez, Juan Carlos; Penick, John

    2007-01-01

    Explosions and fires--these are what many students are waiting for in science classes. And when they do occur, students pay attention. While we can't entertain our students with continual mayhem, we can catch their attention and cater to their desires for excitement by saying, "Let's make rockets." In this activity, students make simple, reusable…

  12. Launch Excitement with Water Rockets

    ERIC Educational Resources Information Center

    Sanchez, Juan Carlos; Penick, John

    2007-01-01

    Explosions and fires--these are what many students are waiting for in science classes. And when they do occur, students pay attention. While we can't entertain our students with continual mayhem, we can catch their attention and cater to their desires for excitement by saying, "Let's make rockets." In this activity, students make simple, reusable

  13. From light modulation to far-field excitation of graphene plasmons: science and applications of graphene-integrated metasurfaces (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Shvets, Gennady

    2015-09-01

    Graphene has emerged as a promising optoelectronic material because its optical properties can be rapidly and dramatically changed using electric gating. Graphene's weak optical response, especially in the infrared part of the spectrum, remains the key challenge to developing practical graphene-based optical devices such as modulators, infrared detectors, and tunable reflect-arrays. We demonstrate experimentally and theoretically demonstrated that a plasmonic metasurface with two Fano resonances can dramatically enhance the interaction of infrared light with single layer graphene. An order of magnitude modulation of the reflected light was accomplished by designing a novel type of a metasurface supporting double Fano resonances and integrating it with an under-layer of graphene. The unique aspect of such modulator is its high baseline reflectivity and large reflectivity extinction coefficient (modulation depth). Using laser interferometry, we demonstrate that the phase of the reflected infrared light can also be modulated by back-gating graphene. This work paves the way to future development of ultrafast opto-electronic devices such as dynamically reconfigurable holograms, single-detector imagers, dynamical beam-steering devices, and reconfigurable biosensors. Moreover, we will show that strong non-local response of graphene can be induced by exciting graphene plasmons which are confined inside the narrow gaps in the plasmonic metasurface. Such graphene plasmons excitation dramatically boosts the intensity of the infrared light confined by the metasurface.

  14. Absolute Cross Sections(Supported by Office of Fusion Energy Sciences, U.S. Dept. of Energy) for Electron Impact Excitation of B^2+ and C^3+

    NASA Astrophysics Data System (ADS)

    Woitke, O.; Chung, Y.-S.; Djuri?, N.; Wallbank, B.; Zhou, S.; Dunn, G. H.; Bannister, M. E.; Smith, A. C. H.

    1998-05-01

    Absolute cross sections for electron-impact excitation of the 2s; ^2S arrow 2p ; ^2P transition in B^2+ and C^3+ have been measured in the threshold region using the merged electron-ion beams energy-loss technique (MEIBEL).(M.E. Bannister et al.), Phys. Rev. A 57, 278 (1998). The data for C^3+ are compared with several sets of previous measurements and found to be in very good agreement with the older results,footnote Taylor et al., Phys. Rev. Lett. 391256 (1977).^,(D. Gregory et al.), Phys. Rev. A 20, 410 (1979). but less so with the more recent ones.(D.W. Savin et al.), Phys. Rev. A 51, 2162 (1995) The B^2+ data are compared with an R-matrix-with-pseudo-states calculation (RMPS) (P.J. Marchalant et al.), J. Phys. B. 30, L435 (1997).^,(K. Bartschat, private communication (1997).) and are found to agree very well.

  15. Project-Based Science

    ERIC Educational Resources Information Center

    Krajcik, Joe

    2015-01-01

    Project-based science is an exciting way to teach science that aligns with the "Next Generation Science Standards" ("NGSS"). By focusing on core ideas along with practices and crosscutting concepts, classrooms become learning environments where teachers and students engage in science by designing and carrying out

  16. Project-Based Science

    ERIC Educational Resources Information Center

    Krajcik, Joe

    2015-01-01

    Project-based science is an exciting way to teach science that aligns with the "Next Generation Science Standards" ("NGSS"). By focusing on core ideas along with practices and crosscutting concepts, classrooms become learning environments where teachers and students engage in science by designing and carrying out…

  17. Double Excitations of Helium

    NASA Astrophysics Data System (ADS)

    Menzel, Alexander

    1996-05-01

    The double excitations of helium offer an ideal case for investigating electron dynamics in a three-body system. Our study of the He ^1P^o double excitations comprises measurements of the partial photoionization cross sections ?n (He^+) and the partial photoelectron angular distribution parameters ?n for the series N(K,T)^Ai up to the N=5 threshold. The experiment was performed at the ALS undulator beam line 9.0.1., which provided a photon flux of 2 10^12 photons per second with a small photon energy bandpass of 7 to 12 meV. This level of differentiation, along with the small bandpass, offers the most critical assessment of the dynamics of the two-electron excitations to date. The principal series K=N-2 are clearly delineated in both ?n and ?_n. The ?n show all minor series with N=K-4 very clearly, in contrast to measurements of the total absorption cross section, as well as very weak members with A=-1. Excellent accord between experiment and theory, particularly the hyperspherical close-coupling method, was found for the dynamic properties in all instances, including the interference pattern due to an overlap of N=5 and N=6 series members. Generally, the Rydberg series of resonance-induced profiles vary greatly depending on the final ionic state He^+(n), whereas the peak-to-valley variation in the ?n within a given series N is of similar magnitude for all n. Interestingly, a striking systematic trend is noted through the various series: the resonance-induced profiles for both the ?n and ?n of the photoelectron satellites are virtually identical provided the final ionic state He^+(n), n >= 2, is reached via an excited series N with ?=1, or ?=2, where ?=N-n. This overall pattern might be attributed to the general similarity of states with the same set of approximately good quantum numbers (N-K), A, and T. We tentatively propose an extension of these systematics for higher series N >= 5, although further theoretical work toward understanding these features of the doubly excited states will be needed. The experiment was performed in close collaboration with C.D. Caldwell, M.O. Krause, S.P. Frigo, and S.B. Whitfield. Valuable theoretical contributions were made by J.-Z. Tang and I. Shimamura. Part of the work appeared in Phys. Rev. Lett. 75, 1479 (1995). This work is supported by the National Science Foundation under grants PHY-9207634 and PHY-9507573.

  18. Systems Science

    ERIC Educational Resources Information Center

    Christakis, Alexander; Hammond, Debora; Jackson, Michael; Laszlo, Alexander; Mitroff, Ian; Snowden, Dave; Troncale, Len; Carr-Chellman, Alison; Spector, J. Michael; Wilson, Brent

    2013-01-01

    Scholars representing the field of systems science were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Alexander Christakis, Debora Hammond, Michael Jackson, Alexander Laszlo, Ian Mitroff, Dave

  19. Organizational Science

    ERIC Educational Resources Information Center

    Beriwal, Madhu; Clegg, Stewart; Collopy, Fred; McDaniel, Reuben, Jr.; Morgan, Gareth; Sutcliffe, Kathleen; Kaufman, Roger; Marker, Anthony; Selwyn, Neil

    2013-01-01

    Scholars representing the field of organizational science, broadly defined as including many fields--organizational behavior and development, management, workplace performance, and so on--were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might

  20. Systems Science

    ERIC Educational Resources Information Center

    Christakis, Alexander; Hammond, Debora; Jackson, Michael; Laszlo, Alexander; Mitroff, Ian; Snowden, Dave; Troncale, Len; Carr-Chellman, Alison; Spector, J. Michael; Wilson, Brent

    2013-01-01

    Scholars representing the field of systems science were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Alexander Christakis, Debora Hammond, Michael Jackson, Alexander Laszlo, Ian Mitroff, Dave…

  1. The Astrophysics Science Division Annual Report 2008

    NASA Technical Reports Server (NTRS)

    Oegerle, William; Reddy, Francis; Tyler, Pat

    2009-01-01

    The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radio wavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. This report includes the Division's activities during 2008.

  2. NMR with excitation modulated by Frank sequences

    NASA Astrophysics Data System (ADS)

    Blmich, Bernhard; Gong, Qingxia; Byrne, Eimear; Greferath, Marcus

    2009-07-01

    Miniaturized NMR is of growing importance in bio-, chemical, and -material sciences. Other than the magnet, bulky components are the radio-frequency power amplifier and the power supply or battery pack. We show that constant flip-angle excitation with phase modulation following a particular type of polyphase perfect sequences results in low peak excitation power at high response peak power. It has ideal power distribution in both the time domain and the frequency domain. A savings in peak excitation power of six orders of magnitude has been realized compared to conventionally pulsed excitation. Among others, the excitation promises to be of use for button-cell operated miniature NMR devices as well as for complying with specific-absorption-rate regulations in high-field medical imaging.

  3. NMR with excitation modulated by Frank sequences.

    PubMed

    Blmich, Bernhard; Gong, Qingxia; Byrne, Eimear; Greferath, Marcus

    2009-07-01

    Miniaturized NMR is of growing importance in bio-, chemical, and -material sciences. Other than the magnet, bulky components are the radio-frequency power amplifier and the power supply or battery pack. We show that constant flip-angle excitation with phase modulation following a particular type of polyphase perfect sequences results in low peak excitation power at high response peak power. It has ideal power distribution in both the time domain and the frequency domain. A savings in peak excitation power of six orders of magnitude has been realized compared to conventionally pulsed excitation. Among others, the excitation promises to be of use for button-cell operated miniature NMR devices as well as for complying with specific-absorption-rate regulations in high-field medical imaging. PMID:19386525

  4. Events | Physical Sciences in Oncology

    Cancer.gov

    The 2015 AAAS Annual Meeting will include exciting work at the intersection of the physical and life sciences, including two sessions organized by NCI Physical Sciences-Oncology Network (PS-ON) Program Directors.

  5. Electron excitation from ground state to first excited state: Bohmian mechanics method

    NASA Astrophysics Data System (ADS)

    Yang, Song; Shuang, Zhao; Fu-Ming, Guo; Yu-Jun, Yang; Su-Yu, Li

    2016-03-01

    The excitation process of electrons from the ground state to the first excited state via the resonant laser pulse is investigated by the Bohmian mechanics method. It is found that the Bohmian particles far away from the nucleus are easier to be excited and are excited firstly, while the Bohmian particles in the ground state is subject to a strong quantum force at a certain moment, being excited to the first excited state instantaneously. A detailed analysis for one of the trajectories is made, and finally we present the space and energy distribution of 2000 Bohmian particles at several typical instants and analyze their dynamical process at these moments. Project supported by the Doctoral Research Start-up Funding of Northeast Dianli University, China (Grant No. BSJXM-201332), the National Natural Science Foundation of China (Grant Nos. 11547114, 11534004, 11474129, 11274141, 11447192, and 11304116), and the Graduate Innovation Fund of Jilin University, China (Grant No. 2015091).

  6. Simultaneous Observations of PKS 2155--304 with H.E.S.S., Fermi, RXTE and ATOM: Spectral Energy Distributions and Variability in a Low State

    SciTech Connect

    Aharonian, F.; Akhperjanian, A.G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A.R.; Becherini, Y.; Behera, B.; Bernlohr, K.; Boisson, C.; Bochow, A.; Borrel, V.; Brion, E.; Brucker, J.; Brun, P.; Buhler, R.; Bulik, T.; Busching, I.; Boutelier, T.; Chadwick, P.M.; Charbonnier, A.; Chaves, R.C.G.; /more authors..

    2009-05-07

    We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of {gamma}-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; >100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little ({approx}30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.

  7. SIMULTANEOUS OBSERVATIONS OF PKS 2155-304 WITH HESS, FERMI, RXTE, AND ATOM: SPECTRAL ENERGY DISTRIBUTIONS AND VARIABILITY IN A LOW STATE

    SciTech Connect

    Aharonian, F.; Bernloehr, K.; Bochow, A.; Buehler, R.; Akhperjanian, A. G.; Anton, G.; Brucker, J.; Barres de Almeida, U.; Chadwick, P. M.; Bazer-Bachi, A. R.; Borrel, V.; Behera, B.; Boisson, C.; Brion, E.; Brun, P.; Buesching, I.; Boutelier, T. E-mail: berrie@in2p3.fr E-mail: jchiang@slac.stanford.edu

    2009-05-10

    We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of {gamma}-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; >100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little ({approx}30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.

  8. Analysis and Interpretation of Hard X-ray Emission fromthe Bullet Cluster (1E0657-56), the Most Distant Cluster of Galaxies Observed by the RXTE

    SciTech Connect

    Petrosian, Vahe; Madejski, Greg; Luli, Kevin; /Stanford U., Phys. Dept.

    2006-08-16

    Evidence for non-thermal activity in clusters of galaxies is well established from radio observations of synchrotron emission by relativistic electrons. New windows in the Extreme Ultraviolet and Hard X-ray ranges have provided for more powerful tools for the investigation of this phenomenon. Detection of hard X-rays in the 20 to 100 keV range have been reported from several clusters of galaxies, notably from Coma and others. Based on these earlier observations we identified the relatively high redshift cluster 1E0657-56 (also known as RX J0658-5557) as a good candidate for hard X-ray observations. This cluster, also known as the bullet cluster, has many other interesting and unusual features, most notably that it is undergoing a merger, clearly visible in the X-ray images. Here we present results from a successful RXTE observations of this cluster. We summarize past observations and their theoretical interpretation which guided us in the selection process. We describe the new observations and present the constraints we can set on the flux and spectrum of the hard X-rays. Finally we discuss the constraints one can set on the characteristics of accelerated electrons which produce the hard X-rays and the radio radiation.

  9. The Fall and the Rise of X-Rays from Dwarf Novae in Outburst: RXTE Observations of VW Hydri and WW Ceti

    NASA Technical Reports Server (NTRS)

    Fertig, D.; Mukai, K.; Nelson, T.; Cannizzo, J. K.

    2011-01-01

    In a dwarf nova, the accretion disk around the white dwarf is a source of ultraviolet, optical, and infrared photons, but is never hot enough to emit X-rays. Observed X-rays instead originate from the boundary layer between the disk and the white dwarf. As the disk switches between quiescence and outburst states, the 2-10 keV X-ray flux is usually seen to be anti-correlated with the optical brightness. Here we present RXTE monitoring observations of two dwarf novae, VW Hyi and WW Cet, confirming the optical/X-ray anti-correlation in these two systems. However, we do not detect any episodes of increased hard X-ray flux on the rise (out of two possible chances for WW Cet) or the decline (two for WW Cet and one for VW Hyi) from outburst, attributes that are clearly established in SS Cyg. The addition of these data to the existing literature establishes the fact that the behavior of SS Cyg is the exception, rather than the archetype as is often assumed. We speculate that only dwarf novae with a massive white dwarf may show these hard X-ray spikes.

  10. RXTE/PCA Monitoring of the Supermassive Star eta Carinae: Unexplained Quasi-Periodic Flares in the Hard X-ray Emission

    NASA Astrophysics Data System (ADS)

    Ishibashi, Kazunori; Corcoran, Michael; Davidson, Kris; Swank, Jean; Petre, Rob; Drake, Steve; Damineli, Augusto

    1999-04-01

    While our intensive monitoring of eta Carinae has mapped the recurrent variation with a 5.5-year period in the hard X-ray lightcurve, we made a serendipitous discovery of 85d periodic flaring activity. In the simplest type of periodic flare model, recurrent disturbances move outward in eta Carinae's wind, and an X-ray flare occurs when each disturbance encounters the shocked wind interaction region. Recent studies suggested that the period between successive flares might lengthen drastically well after Jan 1998 when a postulated binary companion passed periastron. This is due to a ``Doppler-effect''; as the physical separation and velocity vectors of the two stars change due to their orbital motions, any periodic disturbance originating on the primary and propagating through the wind will travel different path lengths to the wind interaction region. Therefore, the orbital motion will in turn result in an observed ``flaring'' period that is modulated as a function of orbital phase. The continuous monitoring with the RXTE/PCA shows that such drastic lengthening of the flaring period may have occurred. The timing of such lengthening may be a crucial key to prove or disprove the binarity hypothesis of eta Carinae.

  11. Acoustically excited heated jets. 1: Internal excitation

    NASA Technical Reports Server (NTRS)

    Lepicovsky, J.; Ahuja, K. K.; Brown, W. H.; Salikuddin, M.; Morris, P. J.

    1988-01-01

    The effects of relatively strong upstream acoustic excitation on the mixing of heated jets with the surrounding air are investigated. To determine the extent of the available information on experiments and theories dealing with acoustically excited heated jets, an extensive literature survey was carried out. The experimental program consisted of flow visualization and flowfield velocity and temperature measurements for a broad range of jet operating and flow excitation conditions. A 50.8-mm-diam nozzle was used for this purpose. Parallel to the experimental study, an existing theoretical model of excited jets was refined to include the region downstream of the jet potential core. Excellent agreement was found between theory and experiment in moderately heated jets. However, the theory has not yet been confirmed for highly heated jets. It was found that the sensitivity of heated jets to upstream acoustic excitation varies strongly with the jet operating conditions and that the threshold excitation level increases with increasing jet temperature. Furthermore, the preferential Strouhal number is found not to change significantly with a change of the jet operating conditions. Finally, the effects of the nozzle exit boundary layer thickness appear to be similar for both heated and unheated jets at low Mach numbers.

  12. Learning Science through History

    ERIC Educational Resources Information Center

    Brodie, Eleanor

    2010-01-01

    This article discusses how the author has developed and managed a collection of exciting resources that aim to aid transition from primary to secondary school by tackling science topics through historical contexts. Working with teachers at both primary and secondary level, the Double Crossed project has designed two exciting cross-curricular

  13. BeppoSAX and RXTE Spectral Study of the Low-mass X-Ray Binary 4U 1705-44: Spectral Hardening during the Banana Branch

    NASA Astrophysics Data System (ADS)

    Seifina, Elena; Titarchuk, Lev; Shrader, Chris; Shaposhnikov, Nikolai

    2015-08-01

    We analyze the X-ray spectra of the atoll 4U 1705-44 when the source undergoes the island-banana state transition. We use the RXTE and BeppoSAX observations for this analysis. We demonstrate that the broadband energy spectral distributions for all evolutinary states can be fitted by a model consisting of two Comptonized components. One arises from the seed photons coming from a neutron star (NS) atmosphere at a temperature {{kT}}{{s}1}≲ 1.5 keV (herein Comptb1), and a second results from the seed photons of {T}{{s}2} ˜ 1.1-1.3 keV coming from the disk (herein Comptb2). We found that we needed to add a low-temperature blackbody and an iron-line (Gaussian) component to the model in order to obtain high-quality fits. The data analysis using this model indicates that the power-law photon index {{{Γ }}}1 of our model is always about 2, independently of the spectral state. Another parameter, {{{Γ }}}2, demonstrates a two-phase behavior depending on the spectral state. {{{Γ }}}2 is quasi-constant at {{{Γ }}}2˜ 2 when the electron temperature {{kT}}{{e}}(2)\\lt 80 keV, and {{{Γ }}}2 is less than 2, in the range of 1.3\\lt {{{Γ }}}2\\lt 2, when {{kT}}{{e}}(2)\\gt 80 keV. This phase is similar to that previously found in the Z-source Sco X-1. We interpret the decreasing index phase using a model in which a super-Eddington radiation pressure from the NS causes an expansion of the Compton cloud similar to that found previously in Sco X-1 during the Flaring branch.

  14. RXTE Observations of Anomalous X-ray Pulsar 1E 1547.0-5408 During and After its 2008 and 2009 Outbursts

    NASA Technical Reports Server (NTRS)

    Dib, Rim; Kaspi, Victoria M.; Scholz, Paul; Gavriil, Fotis P.

    2012-01-01

    We present the results of Rossi X-ray Timing Explorer (RXTE) and Swift monitoring observations of the magnetar 1E 1547.0-5408 following the pulsar's radiative outbursts in 2008 October and 2009 January. We report on a study of the evolution of the timing properties and the pulsed flux from 2008 October 4 through 2009 December 26. In our timing study, a phase-coherent analysis shows that for the first 29 days following the 2008 outburst, there was a very fast increase in the magnitude of the rotational frequency derivative upsilon-dot, such that upsilon-dot-dot was a factor of 60 larger than that reported in data from 2007. This upsilon-dot magnitude increase occurred in concert with the decay of the pulsed flux following the start of the 2008 event. Following the 2009 outburst, for the first 23 days, upsilon-dot-dot was consistent with zero, and upsilon-dot had returned to close to its 2007 value. In contrast to the 2008 event, the 2009 outburst showed a major increase in persistent flux, relatively little change in the pulsed flux, and sudden significant spectral hardening approx 15 days after the outburst. We show that, excluding the month following each of the outbursts, and because of the noise and the sparsity in the data, multiple plausible timing solutions fit the pulsar's frequency behavior. We note similarities in the behavior of 1E 1547.0-5408 following the 2008 outburst to that seen in the AXP 1E 1048.1-5937 following its 2001-2002 outburst and discuss this in terms of the magnetar model.

  15. RXTE Monitoring of the Anomalous X-ray Pulsar 1E 1048.1-5937: Long-Term Variability and the 2007 March Event

    NASA Technical Reports Server (NTRS)

    Dib, Rim; Kaspi, Victoria M.; Gavriil, Fotis P.

    2009-01-01

    After three years of no unusual activity, Anomalous X-ray Pulsar 1E 1048.1-5937 reactivated in 2007 March. We report on the detection of a large glitch (deltav/v = 1.63(2) x 10(exp -5)) on 2007 March 26 (MJD 54185.9), contemporaneous with the onset of a pulsed-flux flare, the third flare observed from this source in 10 years of monitoring with the Rossi X-ray Timing Explorer. Additionally, we report on a detailed study of the evolution of the timing properties, the pulsed flux, and the pulse profile of this source as measured by RXTE from 1996 July to 2008 January. In our timing study, we attempted phase coherent timing of all available observations. We show that in 2001, a timing anomaly of uncertain nature occurred near the rise of the first pulsed flux flare; we show that a likely glitch (deltav/v = 2.91(9) x 10(exp -6)) occurred in 2002, near the rise of the second flare, and we present a detailed description of the variations in the spin-down. In our pulsed flux study, we compare the decays of the three flares and discuss changes in the hardness ratio. In our pulse profile study, we show that the profile exhibited large variations near the peak of the first two flares, and several small short-term profile variations during the most recent flare. Finally, we report on the discovery of a small burst 27 days after the peak of the last flare, the fourth burst discovered from this source. We discuss the relationships between the observed properties in the framework of the magnetar model.

  16. Broadband single-molecule excitation spectroscopy

    NASA Astrophysics Data System (ADS)

    Piatkowski, Lukasz; Gellings, Esther; van Hulst, Niek F.

    2016-01-01

    Over the past 25 years, single-molecule spectroscopy has developed into a widely used tool in multiple disciplines of science. The diversity of routinely recorded emission spectra does underpin the strength of the single-molecule approach in resolving the heterogeneity and dynamics, otherwise hidden in the ensemble. In early cryogenic studies single molecules were identified by their distinct excitation spectra, yet measuring excitation spectra at room temperature remains challenging. Here we present a broadband Fourier approach that allows rapid recording of excitation spectra of individual molecules under ambient conditions and that is robust against blinking and bleaching. Applying the method we show that the excitation spectra of individual molecules exhibit an extreme distribution of solvatochromic shifts and distinct spectral shapes. Importantly, we demonstrate that the sensitivity and speed of the broadband technique is comparable to that of emission spectroscopy putting both techniques side-by-side in single-molecule spectroscopy.

  17. Broadband single-molecule excitation spectroscopy

    PubMed Central

    Piatkowski, Lukasz; Gellings, Esther; van Hulst, Niek F.

    2016-01-01

    Over the past 25 years, single-molecule spectroscopy has developed into a widely used tool in multiple disciplines of science. The diversity of routinely recorded emission spectra does underpin the strength of the single-molecule approach in resolving the heterogeneity and dynamics, otherwise hidden in the ensemble. In early cryogenic studies single molecules were identified by their distinct excitation spectra, yet measuring excitation spectra at room temperature remains challenging. Here we present a broadband Fourier approach that allows rapid recording of excitation spectra of individual molecules under ambient conditions and that is robust against blinking and bleaching. Applying the method we show that the excitation spectra of individual molecules exhibit an extreme distribution of solvatochromic shifts and distinct spectral shapes. Importantly, we demonstrate that the sensitivity and speed of the broadband technique is comparable to that of emission spectroscopy putting both techniques side-by-side in single-molecule spectroscopy. PMID:26794035

  18. Broadband single-molecule excitation spectroscopy.

    PubMed

    Piatkowski, Lukasz; Gellings, Esther; van Hulst, Niek F

    2016-01-01

    Over the past 25 years, single-molecule spectroscopy has developed into a widely used tool in multiple disciplines of science. The diversity of routinely recorded emission spectra does underpin the strength of the single-molecule approach in resolving the heterogeneity and dynamics, otherwise hidden in the ensemble. In early cryogenic studies single molecules were identified by their distinct excitation spectra, yet measuring excitation spectra at room temperature remains challenging. Here we present a broadband Fourier approach that allows rapid recording of excitation spectra of individual molecules under ambient conditions and that is robust against blinking and bleaching. Applying the method we show that the excitation spectra of individual molecules exhibit an extreme distribution of solvatochromic shifts and distinct spectral shapes. Importantly, we demonstrate that the sensitivity and speed of the broadband technique is comparable to that of emission spectroscopy putting both techniques side-by-side in single-molecule spectroscopy. PMID:26794035

  19. NASA and Mary J. Blige Encourage Exciting Careers For Women - Duration: 43 seconds.

    NASA Video Gallery

    NASA is collaborating with award-winning recording artist Mary J. Blige to encourage young women to pursue exciting experiences and career choices through studying science, technology, engineering ...

  20. Helping New Science Teachers

    ERIC Educational Resources Information Center

    Frazier, Wendy M.; Sterling, Donna R.

    2009-01-01

    The start of a new school year is a challenging and exciting time for any teacher--and a time when beginning teachers particularly need our support. Working with new science teachers in the New Science Teachers' Support Network (NSTSN) has shown the authors that veteran teachers have the greatest impact on beginning teacher's success. The NSTSN is…

  1. Science Career Magazine.

    ERIC Educational Resources Information Center

    Halsey, Linda B., Ed.; Sweeley, Charles C., Ed.

    This magazine is designed for teachers and students in junior and senior high schools. It is intended to help students become more aware about what scientists and engineers do, what's new and exciting in the fields of science and engineering, and what satisfactions might be expected from a career in one of the many different areas of science and

  2. 8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER No. 2., AND GENERATOR UNITS BEHIND EXCITER No. 2 IN BACKGROUND. EXCITER No. 1 GENERATOR HAS A COVER OVER TOP HALF OF COMMUTATOR ELEMENT. VIEW TO NORTHWEST. - Rush Creek Hydroelectric System, Powerhouse Exciters, Rush Creek, June Lake, Mono County, CA

  3. Collective excitations in solids

    SciTech Connect

    Di Bartolo, B.

    1983-01-01

    This book is based on the NATO Advanced Study Institute on ''Collective Excitations in Solids'' held in Italy in 1981. The objective of the Institute was to formulate a unified and coherent treatment of various collective excitation processes by drawing on the current advances in various branches of the physics of the solid state. Topics include the quantum mechanical description of solids; an introduction to collective excitations in solids; quasi-particles and excitons (models of structure and correlation); coherent wavepackets of phonons; an introduction to exciton physics; excitons in semiconductors; excitons in insulators; inelastic scattering of fast particles by plasmons; from magnons to solitons; quasiparticles in magnetic metals; polaritons; polarons; surface collective excitations; collective excitations in concentrated Mn/sup 2 +/ systems (spectral properties); optical dynamics in concentrated Mn/sup 2 +/ systems; spectroscopy of stoichiometric laser materials (excitons or incoherent transfers.); exciton-hole droplets in semiconductors; excitons and plasmons (collective excitations in semiconductors); picosecond exciton phenomena in chlorophyll complexes; and present trends in collective excitations in solids.

  4. 16. EXCITERS, AND SYNCHROSCOPE GAUGE ON WALL. ACTIVE ELECTRIC EXCITER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. EXCITERS, AND SYNCHROSCOPE GAUGE ON WALL. ACTIVE ELECTRIC EXCITER AT REAR; UNUSED WATER-DRIVEN EXCITER IN FOREGROUND. VIEW TO SOUTH-SOUTHWEST. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  5. A Comparison of the Variability of the Symbiotic X-ray Binaries GX 1+4, 4U 1954+31, and 4U 1700+24 from Swift/BAT and RXTE/ASM Observations

    NASA Technical Reports Server (NTRS)

    Corbet, R. H. D.; Sokoloski, J. L.; Mukai, K.; Markwardt, C. B.; Tueller, J.

    2007-01-01

    We present an analysis of the X-ray variability of three symbiotic X-ray binaries, GX 1+4, 4U 1700+24, and 4U 1954+31, using observations made with the Swift Burst Alert Telescope (BAT) and the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM). Observations of 4U 1954+31 with the Swift BAT show modulation at a period near 5 hours. Models to explain this modulation are discussed including the presence of an exceptionally slow X-ray pulsar in the system and accretion instabilities. We conclude that the most likely interpretation is that 4U 1954+31 contains one of the slowest known X-ray pulsars. Unlike 4U 1954+31, neither GX 1+4 nor 4U 1700+24 show any evidence for modulation on a timescale of hours. An analysis of the RXTE ASM light curves of GX l+4, 4U 1700+24, and 4U 1954+31 does not show the presence of periodic modulation in any source, although there is considerable variability on long timescales for all three sources. There is no modulation in GX 1+4 on either the optical 1161 day orbital period or a previously reported 304 day X-ray period. For 4U 1700+24 we do not confirm the 404 day period previously proposed for this source from a shorter duration ASM light curve.

  6. Luminosity and spin-period evolution of GX 304-1 during outbursts from 2009 to 2013 observed with the MAXI/GSC, RXTE/PCA, and Fermi/GBM

    NASA Astrophysics Data System (ADS)

    Sugizaki, Mutsumi; Yamamoto, Takayuki; Mihara, Tatehiro; Nakajima, Motoki; Makishima, Kazuo

    2015-08-01

    A report is made on the luminosity and pulse period evolution of the Be binary X-ray pulsar GX 304-1 during a series of outbursts from 2009 to 2013 observed by MAXI/GSC, RXTE/PCA, and Fermi/GBM. In total, 12 outbursts repeated by ˜ 132.2 d were observed, which is consistent with the X-ray periodicity of this object observed in the 1970s. These 12 outbursts, together with those in the 1970s, were all found to recur with a well-defined period of 132.189 ± 0.02 d, which can be identified with the orbital period. The pulse period of ˜ 275 s, obtained from the RXTE/PCA and Fermi/GBM data, apparently exhibited a periodic modulation synchronized with the outburst period, suggesting the pulsar orbital motion, which is superposed on a secular spin-up trend throughout the entire active phase. The observed pulse period changes were successfully represented by a model composed of the binary orbital modulation and pulsar spin up caused by mass accretion through an accretion disk. The orbital elements obtained from the best-fit model, including the projected orbital semi-major axis ax sin i ≃ 500-600 light-s and an eccentricity e ≃ 0.5, are typical of Be binary X-ray pulsars.

  7. Excited State Effective Masses

    SciTech Connect

    Lin, Huey-Wen; Cohen, Saul; Fleming, George

    2007-11-01

    The effective mass description of Euclidean time hadron correlation functions is extended to incorporate multiple excited states and multiple correlation functions. In general, the effective masses will be determined by finding the roots of some polynomial.

  8. Geomagnetic excitation of nutation

    NASA Astrophysics Data System (ADS)

    Ron, C.; Vondrák, J.

    2015-08-01

    We tested the hypothesis of Malkin (2013), who demonstrated that the observed changes of Free Core Nutation parameters (phase, amplitude) occur near the epochs of geomagnetic jerks. We found that if the numerical integration of Brzeziński broad-band Liouville equations of atmospheric/oceanic excitations is re-initialized at the epochs of geomagnetic jerks, the agreement between the integrated and observed celestial pole offsets is improved (Vondrák & Ron, 2014). Nevertheless, this approach assumes that the influence of geomagnetic jerks leads to a stepwise change in the position of celestial pole, which is physically not acceptable. Therefore we introduce a simple continuous excitation function that hypothetically describes the influence of geomagnetic jerks, and leads to rapid but continuous changes of pole position. The results of numerical integration of atmospheric/oceanic excitations and this newly introduced excitation are then compared with the observed celestial pole offsets, and prove that the agreement is improved significantly.

  9. Expanding Science Knowledge: Enabled by Nuclear Power

    NASA Technical Reports Server (NTRS)

    Clark, Karla B.

    2011-01-01

    The availability of Radioisotope Power Sources (RPSs) power opens up new and exciting mission concepts (1) New trajectories available (2) Power for long term science and operations Astonishing science value associated with these previously non-viable missions

  10. Who Am I? ASE Science Year Resources: Bringing Science Year into the Classroom. [CD-ROM].

    ERIC Educational Resources Information Center

    Association for Science Education, Herts (England).

    This CD-ROM describes how science can be used in schools to show that students can be excited and engaged in science and how science can be integrated into other disciplines. Science Year is a 12-month packed calendar of events, projects and resources, designed to stimulate the imagination about science and technology. Activities include the

  11. Who Am I? ASE Science Year Resources: Bringing Science Year into the Classroom. [CD-ROM].

    ERIC Educational Resources Information Center

    Association for Science Education, Herts (England).

    This CD-ROM describes how science can be used in schools to show that students can be excited and engaged in science and how science can be integrated into other disciplines. Science Year is a 12-month packed calendar of events, projects and resources, designed to stimulate the imagination about science and technology. Activities include the…

  12. Effects of abnormal excitation on the dynamics of spiral waves

    NASA Astrophysics Data System (ADS)

    Min-Yi, Deng; Xue-Liang, Zhang; Jing-Yu, Dai

    2016-01-01

    The effect of physiological and pathological abnormal excitation of a myocyte on the spiral waves is investigated based on the cellular automaton model. When the excitability of the medium is high enough, the physiological abnormal excitation causes the spiral wave to meander irregularly and slowly. When the excitability of the medium is low enough, the physiological abnormal excitation leads to a new stable spiral wave. On the other hand, the pathological abnormal excitation destroys the spiral wave and results in the spatiotemporal chaos, which agrees with the clinical conclusion that the early after depolarization is the pro-arrhythmic mechanism of some anti-arrhythmic drugs. The mechanisms underlying these phenomena are analyzed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11365003 and 11165004).

  13. No Compton Reflection In a Chandra/RXTE Observation of Mkn 509: Implications for the Fe-K Line Emission From Accreting X-Ray Sources

    NASA Technical Reports Server (NTRS)

    Yaqoob, Tahir; Padmanabhan, Urmila; Kraemer, Steven B.; Crenshaw, D. Michael; Mckernan, Barry; George, Ian M.; Turner, T. Jane; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We report the results of simultaneous Chandra and RXTE observations of the Seyfert 1 galaxy Mkn 509. We deconvolve the broad and narrow Fe-K emission-line components for which we measure rest-frame equivalent widths of 119+/-18 eV and 57+/-13 eV respectively. The broad line has a FWHM of 57,600((sup 14,400)(sub -21,000)) km/s and the narrow line is unresolved, with an upper limit on the FWHM of 4,940 km/s. Both components must originate in cool matter since we measure rest-frame center energies of 6.36((sup +0.13)(sub -0.12)) keV and 6.42+/-0.01 keV for the broad and narrow line respectively. This rules out He-like and H-like Fe for the origin of both the broad and narrow lines. If, as is widely accepted, the broad Fe-K line originates in Thomson-thick matter (such as an accretion disk), then one expects to observe spectral curvature above approximately 10 keV, (commensurate with the observed broad line), characteristic of the Compton-reflection continuum. However our data sets very stringent limits on deviations of the observed continuum from a power law. Light travel-time delays cannot be invoked to explain anomalies in the relative strengths of the broad Ferry line and Compton-reflection continuum since they are supposed to originate in the same physical location. We are forced to conclude that both the broad and narrow Fe-K lines had to originate in Thomson-thin matter during our observation. This result, for a single observation of just one source, means that our understanding of Fe K line emission and Compton reflection from accreting X-ray sources in general needs to be re-examined. For example, if an irradiated accretion disk existed in Mkn 509 at the time of the observations, the lack of spectral curvature above approximately 10 keV suggests two possibilities. Either the disk was Thomson-thick and highly ionized, having negligible Fe-K line emission and photoelectric absorption or the disk was Thomson-thin producing some or all of the broad Fe-K line emission. In the former case, the broad Fe-K line had to have produced in a Thomson-thin region elsewhere. In both cases the predicted spectral curvature above approximately 10 keV is negligible. An additional implication of our results is that any putative obscuring torus in the system, required by unification models of active galaxies, must also be Thomson-thin. The same applies to the optical broad line region (BLR) if it has a substantial covering factor.

  14. Multi-photon excitation microscopy

    PubMed Central

    Diaspro, Alberto; Bianchini, Paolo; Vicidomini, Giuseppe; Faretta, Mario; Ramoino, Paola; Usai, Cesare

    2006-01-01

    Multi-photon excitation (MPE) microscopy plays a growing role among microscopical techniques utilized for studying biological matter. In conjunction with confocal microscopy it can be considered the imaging workhorse of life science laboratories. Its roots can be found in a fundamental work written by Maria Goeppert Mayer more than 70 years ago. Nowadays, 2PE and MPE microscopes are expected to increase their impact in areas such biotechnology, neurobiology, embryology, tissue engineering, materials science where imaging can be coupled to the possibility of using the microscopes in an active way, too. As well, 2PE implementations in noninvasive optical bioscopy or laser-based treatments point out to the relevance in clinical applications. Here we report about some basic aspects related to the phenomenon, implications in three-dimensional imaging microscopy, practical aspects related to design and realization of MPE microscopes, and we only give a list of potential applications and variations on the theme in order to offer a starting point for advancing new applications and developments. PMID:16756664

  15. The Balloons Go Up for Science.

    ERIC Educational Resources Information Center

    Fayle, Maureen

    1998-01-01

    Describes the planning and implementation of a science week intended to raise the awareness of science in an elementary school. Educational requirements included exciting science happenings and concentrated science teaching of a high standard. The week included demonstrations, guest speakers, and schoolwide assemblies. Demonstrations included the

  16. The Balloons Go Up for Science.

    ERIC Educational Resources Information Center

    Fayle, Maureen

    1998-01-01

    Describes the planning and implementation of a science week intended to raise the awareness of science in an elementary school. Educational requirements included exciting science happenings and concentrated science teaching of a high standard. The week included demonstrations, guest speakers, and schoolwide assemblies. Demonstrations included the…

  17. Excitation Methods for Bridge Structures

    SciTech Connect

    Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

    1999-02-08

    This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

  18. Pulsed Interleaved Excitation

    PubMed Central

    Mller, Barbara K.; Zaychikov, Evgeny; Bruchle, Christoph; Lamb, Don C.

    2005-01-01

    In this article, we demonstrate the new method of pulsed interleaved excitation (PIE), which can be used to extend the capabilities of multiple-color fluorescence imaging, fluorescence cross-correlation spectroscopy (FCCS), and single-pair fluorescence resonance energy transfer (spFRET) measurements. In PIE, multiple excitation sources are interleaved such that the fluorescence emission generated from one pulse is complete before the next excitation pulse arrives. Hence, the excitation source for each detected photon is known. Typical repetition rates used for PIE are between ?1 and 50 MHz. PIE has many applications in various fluorescence methods. Using PIE, dual-color measurements can be performed with a single detector. In fluorescence imaging with multicolor detection, spectral cross talk can be removed, improving the contrast of the image. Using PIE with FCCS, we can eliminate spectral cross talk, making the method sensitive to weaker interactions. FCCS measurements with complexes that undergo FRET can be analyzed quantitatively. Under specific conditions, the FRET efficiency can be determined directly from the amplitude of the measured correlation functions without any calibration factors. We also show the application of PIE to spFRET measurements, where complexes that have low FRET efficiency can be distinguished from those that do not have an active acceptor. PMID:16113120

  19. Science and Science Fiction

    ERIC Educational Resources Information Center

    Oravetz, David

    2005-01-01

    This article is for teachers looking for new ways to motivate students, increase science comprehension, and understanding without using the old standard expository science textbook. This author suggests reading a science fiction novel in the science classroom as a way to engage students in learning. Using science fiction literature and language

  20. Science and Science Fiction

    ERIC Educational Resources Information Center

    Oravetz, David

    2005-01-01

    This article is for teachers looking for new ways to motivate students, increase science comprehension, and understanding without using the old standard expository science textbook. This author suggests reading a science fiction novel in the science classroom as a way to engage students in learning. Using science fiction literature and language…

  1. Variability and Spectral Studies of Luminous Seyfert 1 Galaxy Fairall 9. Search for the Reflection Component is a Quasar: RXTE and ASCA Observation of a Nearby Radio-Quiet Quasar MR 2251-178

    NASA Technical Reports Server (NTRS)

    Leighly, Karen M.

    1999-01-01

    Monitoring observations with interval of 3 days using RXTE (X Ray Timing Explorer) of the luminous Seyfert 1 galaxy Fairall 9 were performed for one year. The purpose of the observations were to study the variability of Fairall 9 and compare the results with those from the radio-loud object 3C 390.3. The data has been received and analysis is underway, using the new background model. An observation of the quasar MR 2251-178 was made in order to determine whether or not it has a reflection component. Older background models gave an unacceptable subtraction and analysis is underway using the new background model. The observation of NGC 6300 showed that the X-ray spectrum from this Seyfert 2 galaxy appears to be dominated by Compton reflection.

  2. Virtual network as excitable medium

    NASA Astrophysics Data System (ADS)

    Shinyaeva, Taisiya S.; Tarasevich, Yuri Yu.

    2016-02-01

    We simulated the spread of an activity in a virtual group using the model of excitable medium. We assumed that the structure of the virtual group corresponds to a scale- free network. In our simulation, the network consists of 100 nodes, the average degree of the nodes is 1.98. We considered the propagation of excitation both in a homogeneous and an inhomogeneous excitable medium. The simulation showed that the initial conditions have a little effect on the behaviour of the model. In inhomogeneous medium, fraction of the excited nodes increases, when permanent excited elements (‘active’ centres) appear in the network. The fraction of the excited nodes increases, when we increase the number of the permanent excited elements. Locations of the active centres do not affect at the level of excitation. External source of activator increases the fraction of the excited nodes in the scale-free network with distribution of parameters.

  3. Capturing Excitement: Oceanography

    ERIC Educational Resources Information Center

    Boyer, Robert E.; Butts, David P.

    1971-01-01

    Describes four elementary school earth science activities. Each student experience is designed to help children answer questions about the ocean floor, continental drift, volcanism and mountain chains. Includes a bibliography of related articles, books, and maps. (JM)

  4. Magnetostrictive resonance excitation

    SciTech Connect

    Schwartz, R.B.; Kuokkala, V.T.

    1990-01-01

    The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere, or spherical shell, the elastic moduli of the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

  5. Magnetostrictive resonance excitation

    SciTech Connect

    Schwarz, R.B.; Kuokkala, V.T.

    1992-09-29

    The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere or spherical shell, the elastic moduli of the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material. 10 figs.

  6. Magnetostrictive resonance excitation

    SciTech Connect

    Schwarz, Ricardo B.; Kuokkala, Veli-Tapani

    1992-01-01

    The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere or spherical shell, the elastic moduli or the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

  7. Magnetostrictive resonance excitation

    SciTech Connect

    Schwartz, R.B.; Kuokkala, V.T.

    1990-12-31

    The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere, or spherical shell, the elastic moduli of the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

  8. Brain Excitability in Stroke

    PubMed Central

    Carmichael, S. Thomas

    2015-01-01

    There is no current medical therapy for stroke recovery. Principles of physiological plasticity have been identified during recovery in both animal models and human stroke. Stroke produces a loss of physiological brain maps in adjacent peri-infarct cortex and then a remapping of motor and sensory functions in this region. This remapping of function in peri-infarct cortex correlates closely with recovery. Recent studies have shown that the stroke produces abnormal conditions of excitability in neuronal circuits adjacent to the infarct that may be the substrate for this process of brain remapping and recovery. Stroke causes a hypo-excitability in peri-infarct motor cortex that stems from increased tonic ?-aminobutyric acid activity onto neurons. Drugs that reverse this ?-aminobutyric acid signaling promote recovery after stroke. Stroke also increases the sensitivity of glutamate receptor signaling in peri-infarct cortex well after the stroke event, and stimulating ?-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate glutamate receptors in peri-infarct cortex promotes recovery after stroke. Both blocking tonic ?-aminobutyric acid currents and stimulating ?-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors promote recovery after stroke when initiated at quite a delay, more than 3 to 5 days after the infarct. These changes in the excitability of neuronal circuits in peri-infarct cortex after stroke may underlie the process of remapping motor and sensory function after stroke and may identify new therapeutic targets to promote stroke recovery. PMID:21987395

  9. Harmonically excited orbital variations

    SciTech Connect

    Morgan, T.

    1985-08-06

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs.

  10. Aperture excited dielectric antennas

    NASA Technical Reports Server (NTRS)

    Crosswell, W. F.; Chatterjee, J. S.; Mason, V. B.; Tai, C. T.

    1974-01-01

    The results of a comprehensive experimental and theoretical study of the effect of placing dielectric objects over the aperture of waveguide antennas are presented. Experimental measurements of the radiation patterns, gain, impedance, near-field amplitude, and pattern and impedance coupling between pairs of antennas are given for various Plexiglas shapes, including the sphere and the cube, excited by rectangular, circular, and square waveguide feed apertures. The waveguide excitation of a dielectric sphere is modeled using the Huygens' source, and expressions for the resulting electric fields, directivity, and efficiency are derived. Calculations using this model show good overall agreement with experimental patterns and directivity measurements. The waveguide under an infinite dielectric slab is used as an impedance model. Calculations using this model agree qualitatively with the measured impedance data. It is concluded that dielectric loaded antennas such as the waveguide excited sphere, cube, or sphere-cylinder can produce directivities in excess of that obtained by a uniformly illuminated aperture of the same cross section, particularly for dielectric objects with dimensions of 2 wavelengths or less. It is also shown that for certain configurations coupling between two antennas of this type is less than that for the same antennas without dielectric loading.

  11. Apparatus for photon excited catalysis

    NASA Technical Reports Server (NTRS)

    Saffren, M. M. (Inventor)

    1977-01-01

    An apparatus is described for increasing the yield of photonically excited gas phase reactions by extracting excess energy from unstable, excited species by contacting the species with the surface of a finely divided solid.

  12. Static excitation test results of the partial rotor model for 70 MW class superconducting generator with quick response excitation

    SciTech Connect

    Nakamura, H.; Matsumoto, H.; Hasegawa, H.; Nakanishi, K.; Inoue, K.; Sakai, M.; Ohshima, S.

    1996-07-01

    The development of superconducting generators has been progressing in Japan since 1988 as a part of the New Sunshine Project of the Agency of Industrial Science Technology. Toshiba has been in charge of research and development of the quick response excitation type superconducting generator in the project. The authors are manufacturing the partial rotor model, which has the same rotor diameter and shorter winding length comparing with the 70 MW class quick response model machine. They assembled completely the inner rotor and carried out its excitation test in a cryostat. In this paper, they report the test result of heater quench, quench current, training, and pulse excitation.

  13. Resonance Pacemakers in Excitable Media

    NASA Astrophysics Data System (ADS)

    Chigwada, Tabitha Ruvarashe; Parmananda, P.; Showalter, Kenneth

    2006-06-01

    Chemical waves are initiated in an excitable medium by resonance with local periodic forcing of the excitability. Experiments are carried out with a photosensitive Belousov-Zhabotinsky medium, in which the excitability is varied according to the intensity of the imposed illumination. Complex resonance patterns are exhibited as a function of the amplitude and frequency of the forcing. Local resonance-induced wave initiation transforms the medium globally from a quiescent excitable steady state to a periodic state of successive traveling waves.

  14. Science in Orbit

    NASA Technical Reports Server (NTRS)

    Weber, Mary Ellen

    2005-01-01

    This talk presents the excitement of doing science in space. It reviews some of the effects of the physical adaptations that the body undergoes to the lower gravity of space. It also discusses the role of the scientist in the space environment. It also discusses the potential uses of space development, particularly with the use of the space station.

  15. Computer/Information Science

    ERIC Educational Resources Information Center

    Birman, Ken; Roughgarden, Tim; Seltzer, Margo; Spohrer, Jim; Stolterman, Erik; Kearsley, Greg; Koszalka, Tiffany; de Jong, Ton

    2013-01-01

    Scholars representing the field of computer/information science were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Ken Birman, Jennifer Rexford, Tim Roughgarden, Margo Seltzer, Jim Spohrer, and…

  16. Computer/Information Science

    ERIC Educational Resources Information Center

    Birman, Ken; Roughgarden, Tim; Seltzer, Margo; Spohrer, Jim; Stolterman, Erik; Kearsley, Greg; Koszalka, Tiffany; de Jong, Ton

    2013-01-01

    Scholars representing the field of computer/information science were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Ken Birman, Jennifer Rexford, Tim Roughgarden, Margo Seltzer, Jim Spohrer, and

  17. Investigating Science with Young Children.

    ERIC Educational Resources Information Center

    Althouse, Rosemary

    Teaching science by a process approach is an exciting adventure for both teachers and their students. Process science is an open ended approach, and the direction learning will take place is determined, for the most part, by the children. This method requires that teachers understand how children learn, know the possibilities a topic offers for

  18. Investigating Science with Young Children.

    ERIC Educational Resources Information Center

    Althouse, Rosemary

    Teaching science by a process approach is an exciting adventure for both teachers and their students. Process science is an open ended approach, and the direction learning will take place is determined, for the most part, by the children. This method requires that teachers understand how children learn, know the possibilities a topic offers for…

  19. Planning a Creative Science Curriculum

    ERIC Educational Resources Information Center

    Iiyambo, Rebekah

    2005-01-01

    A group of science coordinators in the London Borough of Newham decided that they wanted to create an exciting, stimulating and creative curriculum for teaching science across key stages 1 and 2 (5-11 year-olds). They were motivated to do this because they were concerned about an overloaded curriculum, dominated by literacy and numeracy, with…

  20. Electron-impact excitation of xenon

    NASA Astrophysics Data System (ADS)

    Boffard, John B.; Jung, R. O.; Anderson, L. W.; Lin, Chun C.

    2014-05-01

    Xenon electron-impact cross sections are used in the analysis of non-invasive optical emission spectroscopy diagnostics of many xenon plasmas including Hall thrusters. We present measurements of optical emission cross sections as a function of incident electron energy (0-200 eV) for a large number of emission lines in the 250-900 nm wavelength range using a mono-energetic electron beam along with monchromator/PMT detector. The selection of measured cross sections include both excitation into higher neutral levels, and simultaneous ionization/excitation into Xe+, Xe2+, and Xe3+ levels. Measurements were performed at a low pressure to minimize pressure effects often observed in xenon measurements due to radiation trapping of resonant emission lines. This work was supported by the National Science Foundation.

  1. Intermediate Excited States in Rhodopsin Photochemistry

    NASA Astrophysics Data System (ADS)

    Rothberg, L. J.; Yan, M.; Jedju, T. M.; Callender, R. H.; Chao, H.; Alfano, R. R.

    1996-03-01

    Recent work by Wang et.al. footnote Q. Wang et.al., Science 266, 422 (1994) reports rapid coherent photoisomerization in rhodopsin. The bathorhodopsin photoproduct appears in 200 fs and exhibits torsional oscillations which remain synchronized with the initial photoexcitation. We report transient absorption experiments which suggest that the fraction of excited rhodopsin molecules which does not isomerize in this fashion (approximately 1/3) remains in an electronically excited state, probably the twisted state described by Birge and Hubbard,footnote R. R. Birge and L. M. Hubbard, J. Am. Chem. Soc. 102, 2195 (1980) for ~ 3 ps and then reforms rhodopsin. This picture explains the long bleaching recovery time for rhodopsin and the controversial spectral dynamics which are observed in the red.

  2. Get excited: reappraising pre-performance anxiety as excitement.

    PubMed

    Brooks, Alison Wood

    2014-06-01

    Individuals often feel anxious in anticipation of tasks such as speaking in public or meeting with a boss. I find that an overwhelming majority of people believe trying to calm down is the best way to cope with pre-performance anxiety. However, across several studies involving karaoke singing, public speaking, and math performance, I investigate an alternative strategy: reappraising anxiety as excitement. Compared with those who attempt to calm down, individuals who reappraise their anxious arousal as excitement feel more excited and perform better. Individuals can reappraise anxiety as excitement using minimal strategies such as self-talk (e.g., saying "I am excited" out loud) or simple messages (e.g., "get excited"), which lead them to feel more excited, adopt an opportunity mind-set (as opposed to a threat mind-set), and improve their subsequent performance. These findings suggest the importance of arousal congruency during the emotional reappraisal process. PMID:24364682

  3. The Astrophysics Science Division Annual Report 2009

    NASA Technical Reports Server (NTRS)

    Oegerle, William (Editor); Reddy, Francis (Editor); Tyler, Pat (Editor)

    2010-01-01

    The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum - from gamma rays to radio wavelengths - as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions - WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, space-based interferometry, high contrast imaging techniques to search for exoplanets, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. The overriding goals of ASD are to carry out cutting-edge scientific research, provide Project Scientist support for spaceflight missions, implement the goals of the NASA Strategic Plan, serve and support the astronomical community, and enable future missions by conceiving new concepts and inventing new technologies.

  4. Goddard's Astrophysics Science Division Annual Report 2011

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Reddy, Francis; Tyler, Pat

    2012-01-01

    The Astrophysics Science Division(ASD) at Goddard Space Flight Center(GSFC)is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radiowavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, space-based interferometry, high contract imaging techniques to serch for exoplanets, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. The overriding goals of ASD are to carry out cutting-edge scientific research, and provide Project Scientist support for spaceflight missions, implement the goals of the NASA Strategic Plan, serve and suppport the astronomical community, and enable future missions by conceiving new conepts and inventing new technologies.

  5. Excited-State Dynamics in Folic Acid and 6-CARBOXYPTERIN upon Uva Excitation

    NASA Astrophysics Data System (ADS)

    Huang, Huijuan; Vogt, R. Aaron; Crespo-Hernandez, Carlos E.

    2013-06-01

    The excited-state dynamics of folic acid (FA) and 6-carboxypterin (6CP) are poorly understood and work is needed to uncover the relaxation pathways that ultimately lead to their oxidative damage of DNA. In our approach, broad-band transient absorption spectroscopy was used to monitor the evolution of the excited states in FA and 6CP in basic aqueous solution upon excitation at 350 nm. In addition, quantum-chemical calculations were performed to assist in the interpretation of the experimental results and in the postulation of kinetic mechanisms. The combined experimental and computational results support a kinetic model where excitation of FA results in ultrafast charge separation (? = 0.6 ps), which decays back to the ground state primarily by charge recombination with a lifetime of 2.2 ps. A small fraction of the charge transfer state undergoes intersystem crossing to populate the lowest-energy triplet state with a lifetime of 200 ps. On the other hand, a large fraction of the initially excited singlet state in 6CP decays by fluorescence emission with a lifetime of 100 ps, while intersystem crossing to the triplet state occurs with a lifetime of 4.4 ns. The potential implications of these results to the oxidative damage of DNA by FA and 6CP will be discussed. Funding from the National Science Foundation is gratefully acknowledged (CHE-1255084).

  6. Search for Gluonic Excitations

    SciTech Connect

    Eugenio, Paul

    2007-10-26

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenological models for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  7. Search for Gluonic Excitations

    SciTech Connect

    Paul Eugenio

    2007-10-01

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenological models for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  8. Science in Science Fiction.

    ERIC Educational Resources Information Center

    Allday, Jonathan

    2003-01-01

    Offers some suggestions as to how science fiction, especially television science fiction programs such as "Star Trek" and "Star Wars", can be drawn into physics lessons to illuminate some interesting issues. (Author/KHR)

  9. Science in motion

    SciTech Connect

    Anderson, M.; Howe, D.; Mitchell, D.

    1994-12-31

    With the help of grants from the National Science Foundation, the Howard Hughes Medical Institute and other sponsors, we have instituted a program that provides total support for the high school science teacher. Using specially designed vans, certified science teachers deliver modern scientific instrumentation to schools and support the teacher in introducing the students to the use of this equipment. Summer programs and science fairs are available where teachers have the opportunity to use the equipment and develop experiments for their classrooms. The activities of this program offer students and faculty the opportunity to demonstrate the attainment of national standards. This program has been featured on ABC news as a successful program in exciting students about science using a hands-on approach.

  10. Neural Excitability and Singular Bifurcations.

    PubMed

    De Maesschalck, Peter; Wechselberger, Martin

    2015-12-01

    We discuss the notion of excitability in 2D slow/fast neural models from a geometric singular perturbation theory point of view. We focus on the inherent singular nature of slow/fast neural models and define excitability via singular bifurcations. In particular, we show that type I excitability is associated with a novel singular Bogdanov-Takens/SNIC bifurcation while type II excitability is associated with a singular Andronov-Hopf bifurcation. In both cases, canards play an important role in the understanding of the unfolding of these singular bifurcation structures. We also explain the transition between the two excitability types and highlight all bifurcations involved, thus providing a complete analysis of excitability based on geometric singular perturbation theory. PMID:26246435

  11. New topological excitations in quantum Hall systems

    NASA Astrophysics Data System (ADS)

    Lyanda-Geller, Yuli; Lin, Tsuging; Simion, George; Watson, John D.; Manfra, Michael J.; Csathy, Gabor; Rokhinson, Leonid

    2014-03-01

    We discover new topological excitations of two dimensional electrons in the quantum Hall regime. The strain dependence of resistivity observed experimentally is shown to change sign upon crossing filling-factor-specified boundaries of reentrant integer quantum Hall effect (RIQHE) states. This observation violates the known symmetry of electron bubbles thought to be responsible for the RIQHE. We demonstrate theoretically that electron bubbles become elongated in the vicinity of charge defects and form textures of finite size. Calculations confirm that textures lower the energy of excitations. In the two-electron bubble crystal these textures form two-dimensional hedgehogs around defects having one extra electron, and vortices around defects lacking one electron. Strain affects vortices and hedgehogs differently, explaining striking strain-dependent resistivity. The sharp transition from insulating RIQHE state to conducting state is caused by melting of Abrikosov crystal comprised of the defects. The proposed physical mechanism of conductivity due to topological defects is shown to lead to an unusually large magnitude of the strain effect on resistivity in the range of RIQHE filling factors, in agreement with experiment. Research was partially supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Awards DE-SC0010544 (Y.L-G), DE-SC0008630 (L.P.R.), DE-SC0006671 (G.S. and M.M.).

  12. Pattern Formation in Excitable Media

    NASA Astrophysics Data System (ADS)

    Reynolds, William Nash

    1992-01-01

    The phenomenon of excitability is observed in a wide variety of physical and biological systems. In this work, spatially extended excitable systems are examined from several different perspectives. First, a pedagogical introduction is used to motivate the derivation of the dynamics of one dimensional excitable pulses. In the second part, coupled map techniques for numerical simulation of excitable media and other interfacial systems are described. Examples are given for both excitable media and crystal growth. The third chapter addresses the phenomenon of spiral formation in excitable media. Exact rotating solutions are found for a class of models of excitable media. The solutions consist of two regions: an outer region, consisting of the spiral proper, which exhibits a singularity at its tip, and the core region, obtained by rescaling space in the vicinity of the tip. The tip singularity is resolved in the core region, leading to a consistent solution in all of space. The stability of both the spiral and the core is investigated, with the result that the spiral is found to be stable, and the core unstable. Finally, the stability of excitable waves of the chemical cAMP traveling over aggregating colonies of the slime mold Dictyostelium discoideum is examined by coupling the excitable dynamics of the cAMP signalling system to a simple model of chemotaxis, with result that cellular motion is found to destabilize the waves, causing the initially uniform field of cells to break up into streams.

  13. Optically excited states in positronium

    NASA Technical Reports Server (NTRS)

    Howell, R. H.; Ziock, Klaus P.; Magnotta, F.; Dermer, Charles D.; Failor, R. A.; Jones, K. M.

    1990-01-01

    Optical excitation are reported of the 1 3S-2 3P transition in positronium, and a second excitation from n=2 to higher n states. The experiment used light from two pulsed dye lasers. Changes in the positronium annihilation rate during and after the laser pulse were used to deduce the excited state populations. The n=2 level was found to be saturable and excitable to a substantial fraction of n=2 positronium to higher levels. Preliminary spectroscopic measurements were performed on n=14 and n=15 positronium.

  14. A Science Information Infrastructure

    NASA Astrophysics Data System (ADS)

    Christian, C. A.; Hawkins, I.; Malina, R. F.; Dow, K.; Murray, S.

    1994-12-01

    We have created a partnership of science museums, research institutions, teachers, and other centers of informal science education to enable access to the rich resources of remote sensing data available from NASA and other sources and to deliver this information to the general community. We are creating science resource centers in the nation's science museums and planetarium facilities, linking them together through a national Science Information Infrastructure (SII). The SII framework is being founded on Internet connections between the resource centers, which are in turn linked to research institutions. The most up-to-date and exciting science data, related information, and interpretive material will be available from the research institutions. The science museums will present this information in appropriate ways that respond to the needs and interest of the general public and K--12 communities. The science information will be available through the World Wide Web using a Mosaic interface that individuals will use to explore the on-line materials through self-guided learning modules. K--12 teachers will have access to the materials and, in a workshop forum, learn to find and use the information to create lesson plans and curricula for their classrooms. Eventually, as the connectivity of schools and libraries improves, students and teachers will have access to the resource centers from their own locations. The core partnership of the SII includes the Center for EUV Astrophysics (CEA), and Smithsonian Astrophysical Observatory, Exploratorium, Lawrence Hall of Science, Smithsonian National Air and Space Museum, Science Museum of Virginia, New York Hall of Science, Adler Museum of Chicago, University of California Museum of Paleontology, Boston Museum of Science, and the Earth Observing Satellite Company (EOSAT). A demonstration of the application of resource center materials in the K--12 community is being conducted through the Science On-Line project at the Center for EUV Astrophysics. This work has been supported by a NASA Astrophysics Division grant and NASA contract NAS5-29298.

  15. Science and Science Fiction

    SciTech Connect

    Scherrer, Robert

    2006-03-29

    I will explore the similarities and differences between the process of writing science fiction and the process of 'producing' science, specifically theoretical physics. What are the ground rules for introducing unproven new ideas in science fiction, and how do they differ from the corresponding rules in physics? How predictive is science fiction? (For that matter, how predictive is theoretical physics?) I will also contrast the way in which information is presented in science fiction, as opposed to its presentation in scientific papers, and I will examine the relative importance of ideas (as opposed to the importance of the way in which these ideas are presented). Finally, I will discuss whether a background as a research scientist provides any advantage in writing science fiction.

  16. Science and Science Fiction

    ScienceCinema

    Scherrer, Robert [Vanderbilt University, Nashville, Tennessee, United States

    2009-09-01

    I will explore the similarities and differences between the process of writing science fiction and the process of 'producing' science, specifically theoretical physics. What are the ground rules for introducing unproven new ideas in science fiction, and how do they differ from the corresponding rules in physics? How predictive is science fiction? (For that matter, how predictive is theoretical physics?) I will also contrast the way in which information is presented in science fiction, as opposed to its presentation in scientific papers, and I will examine the relative importance of ideas (as opposed to the importance of the way in which these ideas are presented). Finally, I will discuss whether a background as a research scientist provides any advantage in writing science fiction.

  17. Excited waves in shear layers

    NASA Technical Reports Server (NTRS)

    Bechert, D. W.

    1982-01-01

    The generation of instability waves in free shear layers is investigated. The model assumes an infinitesimally thin shear layer shed from a semi-infinite plate which is exposed to sound excitation. The acoustical shear layer excitation by a source further away from the plate edge in the downstream direction is very weak while upstream from the plate edge the excitation is relatively efficient. A special solution is given for the source at the plate edge. The theory is then extended to two streams on both sides of the shear layer having different velocities and densities. Furthermore, the excitation of a shear layer in a channel is calculated. A reference quantity is found for the magnitude of the excited instability waves. For a comparison with measurements, numerical computations of the velocity field outside the shear layer were carried out.

  18. Langevin analysis of fission excitation functions induced by protons

    NASA Astrophysics Data System (ADS)

    Tian, Jian; Wang, Ning; Ye, Wei

    2015-03-01

    The stochastic Langevin approach to fission is applied to analyze fission excitation functions measured in p+206Pb and p+209Bi systems. A presaddle friction strength of (3-5) 1021 s-1 is extracted by comparing theoretical predictions with experimental data. Furthermore, the small distortion of the formed compound nuclei with respect to the spherical shape under the condition of low angular momentum suggests that experimentally, populating an excited compound system via light-ion induced reactions favors a more accurate determination of presaddle friction with a fission cross section. Supported by National Nature Science Foundation of China (11075034)

  19. Vibrational Excitation in Molecular Collisions

    NASA Astrophysics Data System (ADS)

    Hall, Gregory

    The collision energy dependence of the total cross sections for state resolved translation to vibration energy transfer was measured for several neutral systems. Measurements were made for vibrationally inelastic collisions of iodine with helium, neon, and hydrogen isotopes, as well as collisions of aniline and paradifluorobenzene with helium, all in the thermal energy range. Our new experimental technique uses pulsed supersonic molecular beams for initial state selection, crossed at a variable intersection angle for kinematic, continuously tunable collision energy selection. The scattered products are state-selectively detected in the intersection region by laser induced fluoroscence. The iodine cross section energy dependences are approximately linear, quadratic, and cubic for v = 0 to 1, 2, and 3 excitations respectively, as expected from a classical-quantal correspondence principle model. Extreme mode specificity was observed in the polyatoms as only 3 of about 20 energetically accessible vibrations were observed to be collisionally excited. In aniline, the 2 lowest frequency modes were excited. The cross section for single quantum excitations of the inversion mode of the amine group is a strongly decreasing function over the 20 to 250 meV collision energy range. The other observed mode, an out-of-plane bend of the amine group shows a linear onset at threshold for single quantum excitations. The only vibration excited in paradifluorobenzene was the lowest frequency, out-of-plane fluorine bend. Excitation of 1 and 2 quanta was observed. The cross sections both have approximately linear onset at threshold.

  20. Characteristics of excited shear layers

    NASA Astrophysics Data System (ADS)

    Nallasamy, M.

    1989-01-01

    Numerical simulations of the two-dimensional turbulent mixing layer subjected to controlled excitation leading to turbulence suppression are carried out using a vortex-in-cell method. Details of the flow characteristics, in terms of the contours of vorticity, stream function and Reynolds stress are presented and discussed. The results of an experimental study of an axisymmetric mixing layer subjected to high amplitudes of excitation are also presented. The experimental results support the numerical finding that at high amplitudes of excitation the maximum turbulence suppression occurs at a frequency higher than the maximally unstable frequency predicted by the linear theory.

  1. Superfluidity and excitations at unitarity

    SciTech Connect

    Lee, Dean

    2007-04-01

    We present lattice results for spin-1/2 fermions at unitarity, where the effective range of the interaction is zero and the scattering length is infinite. We measure the spatial coherence of difermion pairs for a system of 6, 10, 14, 18, 22, 26 particles with equal numbers of up and down spins in a periodic cube. Using Euclidean time projection, we analyze ground-state properties and transient behavior due to low-energy excitations. At asymptotically large values of t we see long-range order consistent with spontaneously broken U(1) fermion-number symmetry and a superfluid ground state. At intermediate times we see exponential decay in the t-dependent signal due to an unknown low-energy excitation. We probe this low-energy excitation further by calculating two-particle correlation functions. We find that the excitation has the properties of a chain of particles extending across the periodic lattice.

  2. Collisional excitation of interstellar formaldehyde

    NASA Technical Reports Server (NTRS)

    Green, S.; Garrison, B. J.; Lester, W. A., Jr.; Miller, W. H.

    1978-01-01

    Previous calculations for rates of excitation of ortho-H2CO by collisions with He have been extended to higher rotational levels and kinetic temperatures to 80 K. Rates for para-H2CO have also been computed. Pressure-broadening widths for several spectral lines have been obtained from these calculations and are found to agree with recent data within the experimental uncertainty of 10%. Excitation of formaldehyde by collisions with H2 molecules is also discussed.

  3. Exciting Polaritons with Quantum Light

    NASA Astrophysics Data System (ADS)

    López Carreño, J. C.; Sánchez Muñoz, C.; Sanvitto, D.; del Valle, E.; Laussy, F. P.

    2015-11-01

    We discuss the excitation of polaritons—strongly coupled states of light and matter—by quantum light, instead of the usual laser or thermal excitation. As one illustration of the new horizons thus opened, we introduce "Mollow spectroscopy"—a theoretical concept for a spectroscopic technique that consists of scanning the output of resonance fluorescence onto an optical target—from which weak nonlinearities can be read with high precision even in strongly dissipative environments.

  4. Laser-induced nuclear excitation

    SciTech Connect

    Zon, B. A. Kornev, A. S.

    2010-05-15

    An analysis is presented of the Coulomb excitation of low-lying nuclear levels by the electrons produced by strong-field ionization of atoms. It is shown that the resulting short-lived radioactivity can be as high as on the order of 10{sup 3} Ci for certain isotopes excited by using modern laser systems. Relativistic effects are demonstrated that substantially increase radioactivity as compared to that predicted by nonrelativistic theory results.

  5. Electron-excited molecule interactions

    SciTech Connect

    Christophorou, L.G. Tennessee Univ., Knoxville, TN . Dept. of Physics)

    1991-01-01

    In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10{sup 6} to 10{sup 7} times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs.

  6. Redox Control of Cardiac Excitability

    PubMed Central

    Aggarwal, Nitin T.

    2013-01-01

    Abstract Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation. Antioxid. Redox Signal. 18, 432–468. PMID:22897788

  7. SCIENCE CAREERS AT EPA: AN EXCITING OPPORTUNITY TO SERVE

    EPA Science Inventory

    The Environmental Protection Agency has 30 years of history protecting the environment and human health. The scientists at EPA have different backgrounds and experiences that contribute to the creativity of research and development of risk assessment techniques. An overview o...

  8. Science Camp: Just for the Girls

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2007-01-01

    Research shows that girls tend to lose interest in science and math as they move through the education pipeline--a retreat that often begins during middle school. Summer science camps can be part of reversing that trend, some say. Academic camps are on the rise across the country, including ones to get adolescent girls excited about the…

  9. Real-Life Maths and Science

    ERIC Educational Resources Information Center

    Shields, Tanya

    2012-01-01

    As a primary teacher in a large junior school the author would spend many Sunday afternoons planning exciting science lessons only to find they did not include sufficient mathematical knowledge and skills. At the time, the Numeracy Strategy was spreading through classrooms like wildfire. Meanwhile, science lessons were progressing under the

  10. Making Links between Maths and Science

    ERIC Educational Resources Information Center

    Hiscock, Naomi

    2012-01-01

    For some children maths and science are exciting subjects that work side by side, one providing the opportunity to practise and hone skills and knowledge gained from the other. For other children the subjects are disjointed and seem to bear no relationship to each other. Science can provide a wonderful opportunity to practise a variety of math

  11. Reverse Your Science Fair with Educational Partnerships

    ERIC Educational Resources Information Center

    Rose, Jordan; Zardetto-Smith, Andrea; Mu, Keli; Demetrikopoulos, Melissa K.

    2004-01-01

    This article suggests several ways teachers can get their students really excited about science by bringing scientists to the science fair in a different role than the traditional "judge." With a bit more effort, scientists can become actively involved as presenters of hands-on activities. This article discusses: what happens when the tables are

  12. Making Links between Maths and Science

    ERIC Educational Resources Information Center

    Hiscock, Naomi

    2012-01-01

    For some children maths and science are exciting subjects that work side by side, one providing the opportunity to practise and hone skills and knowledge gained from the other. For other children the subjects are disjointed and seem to bear no relationship to each other. Science can provide a wonderful opportunity to practise a variety of math…

  13. Science Camp: Just for the Girls

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2007-01-01

    Research shows that girls tend to lose interest in science and math as they move through the education pipeline--a retreat that often begins during middle school. Summer science camps can be part of reversing that trend, some say. Academic camps are on the rise across the country, including ones to get adolescent girls excited about the

  14. Everyone Loves Science

    NASA Astrophysics Data System (ADS)

    Selen, Mats

    2014-03-01

    Twenty years ago we started a small outreach program at the University of Illinois called ``The Physics Van,'' designed to show the fun of science to assemblies of kids at local elementary schools. Many hundreds of shows - and many hundreds of thousands of excited kids, teachers, and parents later - the program is a cornerstone of the department's outreach efforts. About fourteen years ago I stumbled into a one-time gig with the local CBS television station, which evolved into a weekly live science segment on their morning news show. Very popular with viewers across central Illinois, these science segments now include a colleague from the Department of Chemistry and cover a wide range of topics. The totally unexpected success of both has led me to ponder why these seemingly hapless efforts should have grown to be both successful and sustainable. The conclusions, I believe, are very good news for us all.

  15. NASA Science Served Family Style

    NASA Astrophysics Data System (ADS)

    Noel-Storr, Jacob; Mitchell, S.; Drobnes, E.

    2010-01-01

    Family oriented innovative programs extend the reach of many traditional out-of-school venues to involve the entire family in learning in comfortable and fun environments. Research shows that parental involvement is key to increasing student achievement outcomes, and family-oriented programs have a direct impact on student performance. Because families have the greatest influence on children's attitudes towards education and career choices, we have developed a Family Science program that provides families a venue where they can explore the importance of science and technology in our daily lives by engaging in learning activities that change their perception and understanding of science. NASA Family Science Night strives to change the way that students and their families participate in science, within the program and beyond. After three years of pilot implementation and assessment, our evaluation data shows that Family Science Night participants have positive change in their attitudes and involvement in science.  Even after a single session, families are more likely to engage in external science-related activities and are increasingly excited about science in their everyday lives.  As we enter our dissemination phase, NASA Family Science Night will be compiling and releasing initial evaluation results, and providing facilitator training and online support resources. Support for NASA Family Science Nights is provided in part through NASA ROSES grant NNH06ZDA001N.

  16. Electron impact excitation of helium atom

    NASA Astrophysics Data System (ADS)

    Han, Xiao-Ying; Zeng, De-Ling; Gao, Xiang; Li, Jia-Ming

    2015-08-01

    A method to deal with the electron impact excitation cross sections of an atom from low to high incident energies are presented. This method combines the partial wave method and the first Born approximation (FBA), i.e., replacing the several lowest partial wave cross sections of the total cross sections within FBA by the corresponding exact partial wave cross sections. A new set of codes are developed to calculate the FBA partial wave cross sections. Using this method, the convergent e-He collision cross sections of optical-forbidden and optical-allowed transitions at low to high incident energies are obtained. The calculation results demonstrate the validity and efficiency of the method. Project supported by the National Basic Research Program of China (Grant Nos. 2011CB921501 and 2013CB922200), the National Natural Science Foundation of China (Grant Nos. 11274035, 11275029, 11328401, 11371218, 11474031, 11474032, and 11474034), and the Foundation of Development of Science and Technology of Chinese Academy of Engineering Physics (Grant Nos. 2013A0102005 and 2014A0102005).

  17. Indirect excitation of ultrafast demagnetization

    PubMed Central

    Vodungbo, Boris; Tudu, Bahrati; Perron, Jonathan; Delaunay, Renaud; Müller, Leonard; Berntsen, Magnus H.; Grübel, Gerhard; Malinowski, Grégory; Weier, Christian; Gautier, Julien; Lambert, Guillaume; Zeitoun, Philippe; Gutt, Christian; Jal, Emmanuelle; Reid, Alexander H.; Granitzka, Patrick W.; Jaouen, Nicolas; Dakovski, Georgi L.; Moeller, Stefan; Minitti, Michael P.; Mitra, Ankush; Carron, Sebastian; Pfau, Bastian; von Korff Schmising, Clemens; Schneider, Michael; Eisebitt, Stefan; Lüning, Jan

    2016-01-01

    Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions. PMID:26733106

  18. Stochastic excitation of stellar oscillations

    NASA Astrophysics Data System (ADS)

    Samadi, Reza

    2001-05-01

    Since more than about thirty years, solar oscillations are thought to be excited stochastically by the turbulent motions in the solar convective zone. It is currently believed that oscillations of stars lower than 2 solar masses - which possess an upper convective zone - are excited stochastically by turbulent convection in their outer layers. Providing that accurate measurements of the oscillation amplitudes and damping rates are available it is possible to evaluate the power injected into the modes and thus - by comparison with the observations - to constrain current theories. A recent theoretical work (Samadi & Goupil, 2001; Samadi et al., 2001) supplements and reinforces the theory of stochastic excitation of star vibrations. This process was generalized to a global description of the turbulent state of their convective zone. The comparison between observation and theory, thus generalized, will allow to better know the turbulent spectrum of stars, and this in particular thanks to the COROT mission.

  19. Indirect excitation of ultrafast demagnetization

    DOE PAGESBeta

    Vodungbo, Boris; Tudu, Bahrati; Perron, Jonathan; Delaunay, Renaud; Müller, Leonard; Berntsen, Magnus H.; Grübel, Gerhard; Malinowski, Grégory; Weier, Christian; Gautier, Julien; et al

    2016-01-06

    Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset andmore » at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. As a result, our data thus confirm recent theoretical predictions.« less

  20. Indirect excitation of ultrafast demagnetization

    NASA Astrophysics Data System (ADS)

    Vodungbo, Boris; Tudu, Bahrati; Perron, Jonathan; Delaunay, Renaud; Mller, Leonard; Berntsen, Magnus H.; Grbel, Gerhard; Malinowski, Grgory; Weier, Christian; Gautier, Julien; Lambert, Guillaume; Zeitoun, Philippe; Gutt, Christian; Jal, Emmanuelle; Reid, Alexander H.; Granitzka, Patrick W.; Jaouen, Nicolas; Dakovski, Georgi L.; Moeller, Stefan; Minitti, Michael P.; Mitra, Ankush; Carron, Sebastian; Pfau, Bastian; von Korff Schmising, Clemens; Schneider, Michael; Eisebitt, Stefan; Lning, Jan

    2016-01-01

    Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions.

  1. Excitation optimization for damage detection

    SciTech Connect

    Bement, Matthew T; Bewley, Thomas R

    2009-01-01

    A technique is developed to answer the important question: 'Given limited system response measurements and ever-present physical limits on the level of excitation, what excitation should be provided to a system to make damage most detectable?' Specifically, a method is presented for optimizing excitations that maximize the sensitivity of output measurements to perturbations in damage-related parameters estimated with an extended Kalman filter. This optimization is carried out in a computationally efficient manner using adjoint-based optimization and causes the innovations term in the extended Kalman filter to be larger in the presence of estimation errors, which leads to a better estimate of the damage-related parameters in question. The technique is demonstrated numerically on a nonlinear 2 DOF system, where a significant improvement in the damage-related parameter estimation is observed.

  2. Indirect excitation of ultrafast demagnetization.

    PubMed

    Vodungbo, Boris; Tudu, Bahrati; Perron, Jonathan; Delaunay, Renaud; Müller, Leonard; Berntsen, Magnus H; Grübel, Gerhard; Malinowski, Grégory; Weier, Christian; Gautier, Julien; Lambert, Guillaume; Zeitoun, Philippe; Gutt, Christian; Jal, Emmanuelle; Reid, Alexander H; Granitzka, Patrick W; Jaouen, Nicolas; Dakovski, Georgi L; Moeller, Stefan; Minitti, Michael P; Mitra, Ankush; Carron, Sebastian; Pfau, Bastian; von Korff Schmising, Clemens; Schneider, Michael; Eisebitt, Stefan; Lüning, Jan

    2016-01-01

    Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions. PMID:26733106

  3. Science Anxiety and Science Learning.

    ERIC Educational Resources Information Center

    Mallow, Jeffrey V.; Greenburg, Sharon L.

    1983-01-01

    Discusses origins and nature of science anxiety and describes the Science Anxiety Clinic, outlining techniques used at the clinic. Techniques include science skills training and psychological interventions. Comments on the connection between science anxiety and cognitive processes in science learning. (Author/JN)

  4. Students Excited by Stellar Discovery

    NASA Astrophysics Data System (ADS)

    2011-02-01

    In the constellation of Ophiuchus, above the disk of our Milky Way Galaxy, there lurks a stellar corpse spinning 30 times per second -- an exotic star known as a radio pulsar. This object was unknown until it was discovered last week by three high school students. These students are part of the Pulsar Search Collaboratory (PSC) project, run by the National Radio Astronomy Observatory (NRAO) in Green Bank, WV, and West Virginia University (WVU). The pulsar, which may be a rare kind of neutron star called a recycled pulsar, was discovered independently by Virginia students Alexander Snider and Casey Thompson, on January 20, and a day later by Kentucky student Hannah Mabry. "Every day, I told myself, 'I have to find a pulsar. I better find a pulsar before this class ends,'" said Mabry. When she actually made the discovery, she could barely contain her excitement. "I started screaming and jumping up and down." Thompson was similarly expressive. "After three years of searching, I hadn't found a single thing," he said, "but when I did, I threw my hands up in the air and said, 'Yes!'." Snider said, "It actually feels really neat to be the first person to ever see something like that. It's an uplifting feeling." As part of the PSC, the students analyze real data from NRAO's Robert C. Byrd Green Bank Telescope (GBT) to find pulsars. The students' teachers -- Debra Edwards of Sherando High School, Leah Lorton of James River High School, and Jennifer Carter of Rowan County Senior High School -- all introduced the PSC in their classes, and interested students formed teams to continue the work. Even before the discovery, Mabry simply enjoyed the search. "It just feels like you're actually doing something," she said. "It's a good feeling." Once the pulsar candidate was reported to NRAO, Project Director Rachel Rosen took a look and agreed with the young scientists. A followup observing session was scheduled on the GBT. Snider and Mabry traveled to West Virginia to assist in the follow-up observations, and Thompson joined online. "Observing with the students is very exciting. It gives the students a chance to learn about radio telescopes and pulsar observing in a very hands-on way, and it is extra fun when we find a pulsar," said Rosen. Snider, on the other hand, said, "I got very, very nervous. I expected when I went there that I would just be watching other people do things, and then I actually go to sit down at the controls. I definitely didn't want to mess something up." Everything went well, and the observations confirmed that the students had found an exotic pulsar. "I learned more in the two hours in the control room than I would have in school the whole day," Mabry said. Pulsars are spinning neutron stars that sling lighthouse beams of radio waves or light around as they spin. A neutron star is what is left after a massive star explodes at the end of its normal life. With no nuclear fuel left to produce energy to offset the stellar remnant's weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name neutron star. One tablespoon of material from a pulsar would weigh 10 million tons -- as much as a supertanker. The object that the students discovered is in a special class of pulsar that spins very fast - in this case, about 30 times per second, comparable to the speed of a kitchen blender. "The big question we need to answer first is whether this is a young pulsar or a recycled pulsar," said Maura McLaughlin, an astronomer at WVU. "A pulsar spinning that fast is very interesting as it could be newly born or it could be a very old, recycled pulsar." A recycled pulsar is one that was once in a binary system. Material from the companion star is deposited onto the pulsar, causing it to speed up, or be recycled. Mystery remains, however, about whether this pulsar has ever had a companion star. If it did, "it may be that this pulsar had a massive companion that exploded in a supernova, disrupting its orbit," McLaughlin said. Astronomers and students will work together in the coming months to find answers to these questions. The PSC is a joint project of the National Radio Astronomy Observatory and West Virginia University, funded by a grant from the National Science Foundation. The PSC, led by NRAO Education Officer Sue Ann Heatherly and Project Director Rachel Rosen, includes training for teachers and student leaders, and provides parcels of data from the GBT to student teams. The project involves teachers and students in helping astronomers analyze data from the GBT, a giant, 17-million-pound telescope. Some 300 hours of observing data were reserved for analysis by student teams. Thompson, Snider, and Mabry have been working with about 170 other students across the country. The responsibility for the work, and for the discoveries, is theirs. They are trained by astronomers and by their teachers to distinguish between pulsars and noise. The students' collective judgment sifts the pulsars from the noise. All three students had analyzed thousands of data plots before coming upon this one. Casey Thompson, who has been with the PSC for three years, has analyzed more than 30,000 plots. "Sometimes I just stop and think about the fact that I'm looking at data from space," Thompson said. "It's really special to me." In addition to this discovery, two other astronomical objects have been discovered by students. In 2009, Shay Bloxton of Summersville, WV, discovered a pulsar that spins once every four seconds, and Lucas Bolyard of Clarksburg, WV, discovered a rapidly rotating radio transient, which astronomers believe is a pulsar that emits radio waves in bursts. Those involved in the PSC hope that being a part of astronomy will give students an appreciation for science. Maybe the project will even produce some of the next generation of astronomers. Snider, surely, has been inspired. "The PSC changed my career path," confessed Thompson. "I'm going to study astrophysics." Snider is pleased with the idea of contributing to scientific knowledge. "I hope that astronomers at Green Bank and around the world can learn something from the discovery," he said. Mabry is simply awed. "We've actually been able to experience something," she said. The PSC will continue through 2011. Teachers interested in participating in the program can learn more at this link, http://www.gb.nrao.edu/epo/psc.shtml.

  5. Excited-to-excited-state scattering using weak measurements

    NASA Astrophysics Data System (ADS)

    U, Satya Sainadh; Narayanan, Andal

    2015-11-01

    Weak measurements are a subset of measurement processes in quantum mechanics wherein the system, which is being measured, interacts very weakly with the measuring apparatus. Measurement values of observables undergoing a weak interaction and their amplification are concepts that have sharpened our understanding of interaction processes in quantum mechanics. Recent experiments show that naturally occurring processes such as resonance fluorescence from excited states of an atom can exhibit weak value amplification effect. In this paper we theoretically analyze the process of elastic resonance fluorescence from a V -type three-level atomic system, using the well-known Weiskopff-Wigner (WW) theory of spontaneous emission. Within this theory we show that a weak interaction regime can be identified and for suitable choices of initial and final excited states the mean scattering time between these states show an amplification effect during interaction with the vacuum bath modes of the electromagnetic field. We thus show that a system-bath interaction can show weak value amplification. Using our theory we reproduce the published experimental results carried out in such a system. More importantly, our theory can calculate scattering time scales in elastic resonance scattering between multiple excited states of a single atom or between common excited state configurations of interacting multiatom systems.

  6. Electron impact excitation of coronene

    SciTech Connect

    Khakoo, M.A.; Ratliff, J.M.; Trajmar, S. )

    1990-12-15

    A preliminary study of the electron-impact excitation of thermally evaporated coronene at 550{degree} C was carried out using electron-energy-loss spectroscopy. Measurements of the energy-loss spectra of coronene at high (100 eV) and low (5--20 eV) impact energies are presented. One of the high-energy spectra was converted to an apparent generalized oscillator strength spectrum and compared to the photoabsorption spectrum of coronene. Observations concerning vibrational excitation of coronene by electron impact are also presented and discussed.

  7. Electron impact excitation of coronene

    NASA Technical Reports Server (NTRS)

    Khakoo, M. A.; Ratliff, J. M.; Trajmar, S.

    1990-01-01

    A preliminary study of the electron-impact excitation of thermally evaporated coronene at 550 C was carried out using electron-energy-loss spectroscopy. Measurements of the energy-loss spectra of coronene at high (100 eV) and low (5-20 eV) impact energies are presented. One of the high-energy spectra was converted to an apparent generalized oscillator strength spectrum and compared to the photoabsorption spectrum of coronene. Observations concerning vibrational excitation of coronene by electron impact are also presented and discussed.

  8. Magnetically induced pulser laser excitation

    SciTech Connect

    Taylor, R.S.; Leopold, K.E.

    1985-02-15

    A novel excitation scheme has been developed for excimer discharge lasers. The technique uses pulse transformer technology to induce a fast, high voltage pulse directly onto a ground potential laser electrode resulting in the breakdown of the laser gas mix. Saturation of the pulse transformer core inductance then permits efficient energy transfer from the main energy storage circuit into the discharge. When this excitation technique was used in a XeCl laser an output energy density of 2.5 J/l and an overall electrical to optical efficiency of 2% were obtained. The technique appears promising for the development of high energy, high average power excimer lasers.

  9. Communicating Science

    NASA Astrophysics Data System (ADS)

    Russell, Nicholas

    2009-10-01

    Introduction: what this book is about and why you might want to read it; Prologue: three orphans share a common paternity: professional science communication, popular journalism, and literary fiction are not as separate as they seem; Part I. Professional Science Communication: 1. Spreading the word: the endless struggle to publish professional science; 2. Walk like an Egyptian: the alien feeling of professional science writing; 3. The future's bright? Professional science communication in the age of the internet; 4. Counting the horse's teeth: professional standards in science's barter economy; 5. Separating the wheat from the chaff: peer review on trial; Part II. Science for the Public: What Science Do People Need and How Might They Get It?: 6. The Public Understanding of Science (PUS) movement and its problems; 7. Public engagement with science and technology (PEST): fine principle, difficult practice; 8. Citizen scientists? Democratic input into science policy; 9. Teaching and learning science in schools: implications for popular science communication; Part III. Popular Science Communication: The Press and Broadcasting: 10. What every scientist should know about mass media; 11. What every scientist should know about journalists; 12. The influence of new media; 13. How the media represents science; 14. How should science journalists behave?; Part IV. The Origins of Science in Cultural Context: Five Historic Dramas: 15. A terrible storm in Wittenberg: natural knowledge through sorcery and evil; 16. A terrible storm in the Mediterranean: controlling nature with white magic and religion; 17. Thieving magpies: the subtle art of false projecting; 18. Foolish virtuosi: natural philosophy emerges as a distinct discipline but many cannot take it seriously; 19. Is scientific knowledge 'true' or should it just be 'truthfully' deployed?; Part V. Science in Literature: 20. Science and the Gothic: the three big nineteenth-century monster stories; 21. Science fiction: serious literature of ideas or low-grade entertainment?; 22. Science in British literary fiction; 23. Science on stage: the politics and ethics of science in cultural and educational contexts.

  10. Soapy Science. Teaching Science.

    ERIC Educational Resources Information Center

    Leyden, Michael

    1997-01-01

    Describes a science and math activity that involves bubbles, shapes, colors, and solid geometry. Students build geometric shapes with soda straws and submerge the shapes in soapy water, allowing them to review basic geometry concepts, test hypotheses, and learn about other concepts such as diffraction, interference colors, and evaporation. (TJQ)

  11. High Excitation Gas and ISM

    NASA Technical Reports Server (NTRS)

    Peeters, E.; Martin-Hernandez, N. L.; Rodriguez-Fernandez, N. J.; Tielens, A. G. G. M.

    2004-01-01

    An overview is given of ISO results on regions of high excitation ISM and gas, i.e. HII regions, the Galactic Centre and Supernovae Remnants. IR emission due to fine-structure lines, molecular hydrogen, silicates, polycyclic aromatic hydrocarbons and dust are summarized, their diagnostic capabilities illustrated and their implications highlighted.

  12. Photoacoustic generation using coded excitation

    NASA Astrophysics Data System (ADS)

    Su, Shin-Yuan; Li, Pai-Chi

    2011-03-01

    Photoacoustic (PA) imaging has been used to image soft tissue due to its high contrast and high spatial resolution. The generation of PA signal is based on the object's absorption characteristic to the emitted electromagnetic energy. Typically, a Q-switched Nd:YAG laser providing mJ pulse energy is suitable for biomedical PA applications. However, such laser is relatively bulky and expensive. An alternative way is to use a diode laser. A diode laser can generate laser pulse at much higher pulse repetition frequency (PRF). However, the output power of the diode laser is too low for effective PA generation. One method to overcome this problem is to increase the transmission energy using coded excitation. The coded laser signals can be transmitted by a diode laser with high PRF and the signal intensity of the received signal can be enhanced using pulse compression. In this study, we proposed a chirp coded excitation algorithm for a diode laser. Compared to Golay coded excitation seen in the literature, the proposed chirp coded excitation requires only a single transmission. Chirp-coded PA signal was generated by tuning the pulse duration of individual laser pulses in time domain. Result shows that the PA signal intensity can be enhanced after matched filtering. However, high range side-lobes are still present. The compression filter is an important tool to reduce the range side-lobes, which is subject to further investigation.

  13. Elementary Excitations in Quantum Liquids.

    ERIC Educational Resources Information Center

    Pines, David

    1981-01-01

    Discusses elementary excitations and their role in condensed matter physics, focusing on quantum plasma, helium liquids, and superconductors. Considers research primarily conducted in the 1950s and concludes with a brief survey of some closely related further developments. (Author/JN)

  14. Lifetime of excited atomic states

    SciTech Connect

    Cresser, J.D.; Tang, A.Z.; Salamo, G.J.; Chan, F.T.

    1986-03-01

    In this paper we derive an expression for the lifetime of excited atomic states taking account of contributions due to nonresonant two-photon transitions. Explicit integration of the two-photon emission spectrum is not required. The results are applied to the case of the hydrogen atom.

  15. Population dynamics of excited atoms in non-Markovian environments at zero and finite temperature

    NASA Astrophysics Data System (ADS)

    Zou, Hong-Mei; Fang, Mao-Fa

    2015-08-01

    The population dynamics of a two-atom system, which is in two independent Lorentzian reservoirs or in two independent Ohmic reservoirs respectively, where the reservoirs are at zero temperature or finite temperature, is studied by using the time-convolutionless master-equation method. The influences of the characteristics and temperature of a non-Markovian environment on the population of the excited atoms are analyzed. We find that the population trapping of the excited atoms is related to the characteristics and the temperature of the non-Markovian environment. The results show that, at zero temperature, the two atoms can be effectively trapped in the excited state both in the Lorentzian reservoirs and in the Ohmic reservoirs. At finite temperature, the population of the excited atoms will quickly decay to a nonzero value. Project supported by the Science and Technology Plan of Hunan Province, China (Grant No. 2010FJ3148) and the National Natural Science Foundation of China (Grant No. 11374096).

  16. Science Matters

    ERIC Educational Resources Information Center

    Odell, Bill

    2005-01-01

    The spaces and structures used for undergraduate science often work against new teaching methods and fail to provide environments that attract the brightest students to science. The undergraduate science building often offers little to inspire the imaginations of young minds. The typical undergraduate science building also tends to work against

  17. Science Sacks

    ERIC Educational Resources Information Center

    Freudenberg, Kimberlee

    2012-01-01

    With the emphasis placed on standardized testing, science education has been squeezed out. As a physics teacher, the author knows the importance of building children's interest in science early in their school career and of providing practice in basic science skills and inquiry. In order to make more time for science at her sons' elementary

  18. Science: Secondary.

    ERIC Educational Resources Information Center

    Curriculum Review, 1980

    1980-01-01

    This article reviews and compares five recent secondary science texts: Addison-Wesley Life Science (Gr. 7-9); Prentice-Hall Life Science (Gr. 7-9); Scott Foresman Biology (Gr. 9-12); Biology: Living Systems (Gr. 10-12); and Biology: The Science of Life (Gr. 10-12). (SJL)

  19. Science Matters

    ERIC Educational Resources Information Center

    Odell, Bill

    2005-01-01

    The spaces and structures used for undergraduate science often work against new teaching methods and fail to provide environments that attract the brightest students to science. The undergraduate science building often offers little to inspire the imaginations of young minds. The typical undergraduate science building also tends to work against…

  20. Science Sacks

    ERIC Educational Resources Information Center

    Freudenberg, Kimberlee

    2012-01-01

    With the emphasis placed on standardized testing, science education has been squeezed out. As a physics teacher, the author knows the importance of building children's interest in science early in their school career and of providing practice in basic science skills and inquiry. In order to make more time for science at her sons' elementary…

  1. Band excitation Kelvin probe force microscopy utilizing photothermal excitation

    NASA Astrophysics Data System (ADS)

    Collins, Liam; Jesse, Stephen; Balke, Nina; Rodriguez, Brian J.; Kalinin, Sergei; Li, Qian

    2015-03-01

    A multifrequency open loop Kelvin probe force microscopy (KPFM) approach utilizing photothermal as opposed to electrical excitation is developed. Photothermal band excitation (PthBE)-KPFM is implemented here in a grid mode on a model test sample comprising a metal-insulator junction with local charge-patterned regions. Unlike the previously described open loop BE-KPFM, which relies on capacitive actuation of the cantilever, photothermal actuation is shown to be highly sensitive to the electrostatic force gradient even at biases close to the contact potential difference (CPD). PthBE-KPFM is further shown to provide a more localized measurement of true CPD in comparison to the gold standard ambient KPFM approach, amplitude modulated KPFM. Finally, PthBE-KPFM data contain information relating to local dielectric properties and electronic dissipation between tip and sample unattainable using conventional single frequency KPFM approaches.

  2. Band excitation Kelvin probe force microscopy utilizing photothermal excitation

    SciTech Connect

    Collins, Liam E-mail: liq1@ORNL.gov; Rodriguez, Brian J.; Jesse, Stephen; Balke, Nina; Kalinin, Sergei; Li, Qian E-mail: liq1@ORNL.gov

    2015-03-09

    A multifrequency open loop Kelvin probe force microscopy (KPFM) approach utilizing photothermal as opposed to electrical excitation is developed. Photothermal band excitation (PthBE)-KPFM is implemented here in a grid mode on a model test sample comprising a metal-insulator junction with local charge-patterned regions. Unlike the previously described open loop BE-KPFM, which relies on capacitive actuation of the cantilever, photothermal actuation is shown to be highly sensitive to the electrostatic force gradient even at biases close to the contact potential difference (CPD). PthBE-KPFM is further shown to provide a more localized measurement of true CPD in comparison to the gold standard ambient KPFM approach, amplitude modulated KPFM. Finally, PthBE-KPFM data contain information relating to local dielectric properties and electronic dissipation between tip and sample unattainable using conventional single frequency KPFM approaches.

  3. Biopolitical science.

    PubMed

    Arnhart, Larry

    2010-03-01

    This article develops a theoretical framework for biopolitical science as a science of political animals. This science moves through three levels of deep political history: the universal political history of the species, the cultural political history of the group, and the individual political history of animals in the group. To illustrate the particular application of biopolitical science, this essay shows how this science would help us to understand Abraham Lincoln's Emancipation Proclamation of January 1, 1863. PMID:20812796

  4. Science Poetry in Two Voices: Poetry and the Nature of Science

    ERIC Educational Resources Information Center

    Frazier, Wendy M.; Murray, Kristen B.

    2009-01-01

    Poetry can be used during science instruction to foster interest, excitement, and wonder among elementary-level students. Children can read poetry, or have poetry read to them, as a way of learning about their world. They can also create poems to share their own science learning with others. We introduce two formats of the Poetry in Two Voices

  5. Connecting Science and Literacy in the Classroom: Using Space and Earth Science to Support Language Arts

    NASA Astrophysics Data System (ADS)

    Wessen, A. S.; Cobabe-Ammann, E. A.

    2009-12-01

    The connections between science and literacy in the classroom have received increasing attention over the last two decades, as more and more evidence demonstrates that science provides an exciting vehicle in which to engage students on the path to literacy improvement. Combining literacy with science allows students to creatively explore the world or universe, and it. Combining science and literacy improves both reading and science scores, and increases students’ interest in science. At a time when over 40% of students beyond the 5th grade are reading two or more levels below grade level and are struggling with their current materials, finding ways to excite and engage them in the reading process is key. Literacy programs incorporating unique space science content can help prepare children for standardized language arts tests. It also engages our nation’s youngest learners and their teachers with the science, math, and technology of exploration in a language arts format. This session focuses on programs and products that bring the excitement of earth and space science into the literacy classroom, with a focus on research-based approached to combining science and language arts. Reading, Writing and Rings! Grades 1-2

  6. Effecting change in elementary school science education

    SciTech Connect

    Parravano, C.

    1994-12-31

    The mission of the Merck Institute for Science Education is to improve the quality of science education during the formative years of kindergarten through eighth grade. To accomplish this mission, the Institute has three primary goals: Transform the teaching of science to communicate the excitement and relevance of science; Reform the education of teachers to instill in tomorrow`s teachers an understanding and appreciation of science; and Create a consensus on the importance of elementary science education among leaders in education, business, and science. Merck has made a minimum ten year commitment of funding and resources to the Institute. The Institute will work very closely with faculty, administration, and community leaders in target school districts to enhance science education in the elementary grades of their schools. Once the Institute`s goals have been achieved in these initial partner districts, the Institute will replicate its programs in other districts.

  7. Science Fiction and Science Education.

    ERIC Educational Resources Information Center

    Cavanaugh, Terence

    2002-01-01

    Uses science fiction films such as "Jurassic Park" or "Anaconda" to teach science concepts while fostering student interest. Advocates science fiction as a teaching tool to improve learning and motivation. Describes how to use science fiction in the classroom with the sample activity Twister. (YDS)

  8. Solitonlike excitations in biological systems

    NASA Astrophysics Data System (ADS)

    Balanovski, Eduardo; Beaconsfield, Peter

    1985-11-01

    A model for solitonlike excitation in DNA is presented and assessed in the context of previous models of collective excitations in other biological systems. A qualitative analysis describes the mechanisms of some DNA function, in particular opening of DNA base pairs to initiate protein synthesis. A formalism is presented which analyzes quantitatively the above-mentioned model, predicts the threshold for B-DNA-->A-DNA transition, and specifies the parameters of particular electromagnetic stimulations that can produce or initiate a variety of DNA responses and effects. The example of insulin production is discussed in detail and theoretical predictions are given for the parameters of an electromagnetic signal reproducing the stimulation to a cell which would lead to insulin production as a response.

  9. UV excitable fluorescence of lumirubin.

    PubMed

    Bacci, M; Linari, R; Agati, G; Fusi, F

    1989-06-01

    Solutions of bilirubin in different solvents show negligible fluorescence when they are excited with UV light. After irradiation, blue-violet fluorescence (400-450 nm) is observed, whose intensity and peak position depend on the irradiation time. The isolation of pure lumirubin led us to attribute this fluorescence specifically to this photoisomer, even if small contributions from other photoproducts cannot be ruled out. The emission peak of the pure lumirubin in aqueous solution (phosphate buffer) is at 415 nm while the main excitation peak is at 315 nm. Finally, an interpretation of the observed fluorescence is proposed on the basis of the similarity of the present results with previously reported experimental data. PMID:2504903

  10. Spatiotemporal control of nanooptical excitations

    PubMed Central

    Aeschlimann, Martin; Bauer, Michael; Bayer, Daniela; Brixner, Tobias; Cunovic, Stefan; Dimler, Frank; Fischer, Alexander; Pfeiffer, Walter; Rohmer, Martin; Schneider, Christian; Steeb, Felix; Strber, Christian; Voronine, Dmitri V.

    2010-01-01

    The most general investigation and exploitation of light-induced processes require simultaneous control over spatial and temporal properties of the electromagnetic field on a femtosecond time and nanometer length scale. Based on the combination of polarization pulse shaping and time-resolved two-photon photoemission electron microscopy, we demonstrate such control over nanoscale spatial and ultrafast temporal degrees of freedom of an electromagnetic excitation in the vicinity of a nanostructure. The time-resolved cross-correlation measurement of the local photoemission yield reveals the switching of the nanolocalized optical near-field distribution with a lateral resolution well below the diffraction limit and a temporal resolution on the femtosecond time scale. In addition, successful adaptive spatiotemporal control demonstrates the flexibility of the method. This flexible simultaneous control of temporal and spatial properties of nanophotonic excitations opens new possibilities to tailor and optimize the lightmatter interaction in spectroscopic methods as well as in nanophotonic applications. PMID:20212153

  11. FOREWORD Nanomaterials science Nanomaterials science

    NASA Astrophysics Data System (ADS)

    Rohrer, Heinrich

    2010-10-01

    The nanometer regime covers the transition from condensed matter behavior to atomic and molecular properties and thus is a very rich but also very demanding area in materials science. Close to the condensed matter side, properties and functions might still very well be scalable, whereas close to the atomic and molecular side, the scalability is mostly lost. Properties and functions change qualitatively or quantitatively by orders of magnitude when the dimensions become smaller than a critical size in the nanometer range. Examples are the ballistic regime for electron or spin transport at dimensions below the mean free path, near-field effects in scanning near-field optical microscopy and quantum wells when the dimensions are below an appropriate wavelength, novel electronic, mechanical, and chemical properties when the number of bulk atoms becomes smaller than that of surface atoms, quantum conduction, and Coulomb blockade. Thus, by going below a certain size, an abundance of novel properties and functions are at one's disposal, or, in other words, we can functionalize materials simply by reducing their size to the nanoscale. The key to the future lies in the functions that we give to materials, not just in finding 'novel functional materials'. This catch expression in many materials science programs and initiatives of the past two decades sounds great, but it is not what really counts. All materials are functional in one way or another and, therefore, all new materials are 'novel functional materials'. Certainly, finding new materials is always an important part of progress, but we should also focus on the much larger domain of novel functions that we can give to existing or modified materials. A good example is semiconductors: they are fifty or more years old and their properties are very well known, but they were not of widespread interest and use until the transistor changed their destiny into being the central material in the information technology revolution. Interfaces gave them their functions, and shaping them into ever-smaller functional components made them indispensably omnipresent as transistors—produced in billions per person and per year—and they are no doubt the rulers of today's technical world. The semiconductor and transistor serve as an inspiring example of functionalizing materials. The developments of microelectronics profited very much from scalability, that is, the properties and functions do not change significantly with size. Therefore, every step toward smaller dimensions was a technical and commercial challenge with risks well under control. The transition to the nanoscale, however, is discontinuous. Examples of this transition are the local probe methods that exploit the mechanically controlled proximity to the object under consideration and that have become indispensable as microscopes and as measuring and modifying tools, the size of molecular components that are much smaller than the smallest possibly achievable transistor, the properties and functions of materials below a critical size as mentioned above, the continuum properties versus discrete ones, and novel concepts inspired by living nature. Those novel concepts include growing circuits first and building the active components at the nodes afterwards and measuring weak by weak, small by small, and many by many. It is these discontinuous steps that make the nanoscale different, not just smaller. They pose exciting challenges, open great opportunities and nearly unlimited possibilities, but they also carry serious technical, commercial, environmental, and health risks. The nanoscale is also a great opportunity for materials science in general. Materials science is interdisciplinary per se. A materials scientist should have a reasonable understanding of physics, chemistry, engineering, and more recently, also biology. Certainly one can always team up with representatives from other disciplines and forge collaborations. However, an effective team can only emerge from a common understanding of the respective languages and problems. The lack of such an understanding is the Achilles' heel of so many collaborations. Despite the intrinsic interdisciplinary nature, materials science has split into various segments according to the type of material, for example, metals, organic, inorganic, biological, molecular, and so on. Each of them leads an independent life with little understanding for the others. This segmentation has made materials science lose, to an undesirable extent, its all-embracing mission for science and technology. There are laudable efforts to reunite different branches of materials science into comprehensive institutions; examples are NIMS in Tsukuba and IMR at Tohoku University, but institutions alone do not make the day. The nanoscale provides an excellent opportunity for scientists. The nanoscale was the bifurcation point where disciplines split and developed their own disciplinary views and language. This was the necessary core for the tremendous developments of science. Technology always had to rely on broader views. Now, disciplines merge again at the nanoscale, which will hopefully bring back to materials science much of what was lost over recent decades. It is difficult to delimit the nanodomain using general criteria since everything consists of atoms that are roughly a third of a nanometer in size, as is their distance from each other in condensed matter. In most cases, the individual addressabilities of nanostructures, properties, and processes are important. Atoms emerged from the anonymity as members of an ensemble; they have become our partners as individuals. As upper limits for nano, we might agree on 100-200 nm in object size and 1-10 nm in accuracy for local positioning, measuring, modifying, and controlling processes. The lower limit is open; a hundredth of a nanometer in positioning and measuring is nothing extraordinary. As a reviewer, I would accept a very interesting and daring research proposal, even if it interprets 'nano' somewhat too generously. After all, we want to promote top-class research and not average research just for the sake of 'nano'. Interfaces, material growth at given nano positions, shaping materials to a given nanosize and form, and bistability are key elements for functionalizing materials. InterfacesThe role of interfaces is rapidly increasing in science and technology. The number of interfaces increases with the square of the number of phases of materials. Even if the majority of them are impractical or useless, they are still much more abundant than the materials themselves, and they are the key to new functions. Think of the simple 'mechanical' interface responsible for the lotus effect where wetting is prevented by the rapidly changing surface curvature due to nanoparticles. Think of all the connections of a nanometer-sized area between very different materials, for example, for electron or spin transport. Think of the delicate interfaces that protect nanofunctional units from the environment but allow for communication of various types with other nanocomponents or with the macroscopic world. The solid-liquid interface plays a special role here. For me, it is the interface of the future, both for local growth and removal of nm3 quantities and for working with biological specimens requiring a liquid environment. Interfaces are the 'faces of action' and nanoscale materials science will be, to a great extent, 'interface science'. There is no need to change the name; attentive awareness suffices. Material growth at given nano positionsThis is the second central challenge in nanoscale materials science, but maybe still a futuristic one. We have heard much about the extraordinary properties of carbon nanotubes. They do a great job in certain applications, like tips of scanning tunneling and atomic force microscopes or nanoinjection needles or as bundles for electron emission or electron transport. As single carbon nanotubes of various lengths in complex micro- and nano-electronic circuits, however, they have to be grown at given positions, which is still problematic. Another example concerns the assembly scenario for electronics, components like sensors, actuators, and nano-systems. Macromolecular chemistry is producing highly functional macromolecules, but, eventually, they have to be produced and assembled at given positions. Shaping materials to a given nanosize and formIn the field of micro- and nanoelectronics, shaping semiconductors, many oxides, and selected metals down to 20-100 nm dimensions is standard. In nanomechanics, however, other materials might be more appropriate and better suited for a given task. In other cases, finishing procedures might be impossible or too time-consuming for large numbers of them. Components for counting electrons—more elegant and smaller than today's single-electron transistors—or adjustable holes for counting atoms and molecules will eventually be badly needed because of the 1/√N fluctuations in the properties and measurements at a small N, for example, N dopants in nanosize transistors or N electrons in very short current pulses. Bistable componentsBistable components, which do not require electrical currents, are aimed at reducing local energy dissipation and faster startup of personal computers. Magnetoresistive and ferroelectric random access memory (MRAMS and FRAMS) devices are the first attempts to use them in circuits. I am not aware of reported switching times that are considerably faster than a few nanoseconds, as required in today's storage. This is too slow for memory and much too slow for possible logic devices based on two-terminal bistable components. Bistable molecules, a mechanical switch, might be a valid and sufficiently fast alternative, certainly with all the challenges mentioned above. I have mentioned just a few obvious examples of the involvement of materials science in the new world of nanodimensions. However, for materials scientists, the sky is the limit. The thoughts given above are partly reflected in the lectures that I have recently given in Japan. It is my pleasure to thank my colleagues for the mutual understanding and hospitality that I always experience in Japan.

  12. Oscillator response to nonstationary excitation

    NASA Technical Reports Server (NTRS)

    Spanos, P.-T. D.; Solomos, G. P.

    1984-01-01

    Analytical solutions are presented regarding probability density distributions of various response parameters of a lightly damped oscillator. The oscillator is subjected to a broad-band stochastic excitation which possesses a time-variant power spectrum. The analytical solutions are derived by utilizing appropriate Fokker-Planck equations which govern Markovian approximations of the response parameters considered. The reliability of the approximate analytical solution is tested by using pertinent data generated by a digital Monte Carlo study.

  13. Electron impact excitation of Hg/+/

    NASA Technical Reports Server (NTRS)

    Crandall, D. H.; Phaneuf, R. A.; Dunn, G. H.

    1974-01-01

    A crossed charged beam technique was employed in the investigation reported. The ion beam was crossed at right angles by a magnetically confined electron beam. Cross sections were determined as a function of electron impact energy. Considerable structure in the excitation cross section appears immediately above the threshold. It is pointed out that a primary application of cross sections is related to the calculation of plasma rate coefficients.

  14. Excitations in Confined Fermi Fluids

    NASA Astrophysics Data System (ADS)

    Hernndez, E. S.

    2002-12-01

    Studies of excitation spectra of Fermi fluids in the presence of various types of spatial symmetry breaking are reviewed. In particular, I discuss the predicted spectra of films of 3He adsorbed on planar substrates and of dilute 40K gases in magnetic traps. Finally, I anticipate some dynamical aspects of 3He gases in onedimensional and quasi-onedimensional adsorbed phases in porous media.

  15. Channelopathies of skeletal muscle excitability

    PubMed Central

    Cannon, Stephen C.

    2016-01-01

    Familial disorders of skeletal muscle excitability were initially described early in the last century and are now known to be caused by mutations of voltage-gated ion channels. The clinical manifestations are often striking, with an inability to relax after voluntary contraction (myotonia) or transient attacks of severe weakness (periodic paralysis). An essential feature of these disorders is fluctuation of symptoms that are strongly impacted by environmental triggers such as exercise, temperature, or serum K+ levels. These phenomena have intrigued physiologists for decades, and in the past 25 years the molecular lesions underlying these disorders have been identified and mechanistic studies are providing insights for therapeutic strategies of disease modification. These familial disorders of muscle fiber excitability are “channelopathies” caused by mutations of a chloride channel (ClC-1), sodium channel (NaV1.4), calcium channel (CaV1.1) and several potassium channels (Kir2.1, Kir2.6, Kir3.4). This review provides a synthesis of the mechanistic connections between functional defects of mutant ion channels, their impact on muscle excitability, how these changes cause clinical phenotypes, and approaches toward therapeutics. PMID:25880512

  16. Coulomb Excitation of 93Nb

    NASA Astrophysics Data System (ADS)

    Yoshizawa, Yasukazu; Herskind, Bent; Hoshi, Masaharu

    1981-07-01

    Low-lying states of 93Nb have been studied by the Coulomb excitation with oxygen ions. Cross sections were measured for six levels at 774 keV (7/2+), 809 keV (5/2+), 950 keV (13/2+), 979 keV (11/2+), 1083 keV (9/2'+) and 1297 keV. The B(E2) values obtained from the gamma-ray singles spectra are 188 10 (9/2+?7/2+), 153 8 (9/2+?5/2+{'}), 236 13 (9/2+?13/2+), 186 10 (9/2+?11/2+), 30.6 2.1 (9/2+?9/2+{'}) and 40.1 4.0 (9/2+?the 1297 keV level) in the unit of e2\\cdotfm4, where 9/2+ denotes the ground state. Gamma-ray angular correlations were also measured and the spin and parity has been assigned as 9/2+ for the 1297 keV level. In addition, the excitation cross section of the first 2+ state for 92Zr was measured for comparison with the excited states of 93Nb. The deduced B(E2) value is 796 60 (0+?2+). Level properties are discussed and compared with the unified model and the quasi-particle shell model.

  17. Chiral Lagrangian for excited pions

    SciTech Connect

    Volkov, M.K.; Weiss, C.

    1997-07-01

    We construct a chiral Lagrangian containing, in addition to the usual pion field ({pi}), also its first radial excitation ({pi}{sup {prime}}). The Lagrangian is derived in the large-N{sub c} limit from a Nambu{endash}Jona-Lasinio (NJL) quark model with separable nonlocal interactions, with form factors corresponding to three-dimensional ground- and excited-state wave functions. Chiral symmetry breaking is governed by the NJL gap equation. The effective Lagrangian for {pi} and {pi}{sup {prime}} mesons shows the decoupling of the Goldstone pion and the vanishing of the {pi}{sup {prime}} leptonic decay constant f{sub {pi}{sup {prime}}} in the chiral limit, as required by axial-vector current conservation. We derive the excited-state contribution to the axial-vector current of the model using Noether{close_quote}s theorem. For a finite pion mass and {pi}{sup {prime}} masses in the range of 750{endash}1300 MeV, f{sub {pi}{sup {prime}}}/f{sub {pi}} is found to be of the order of 1{percent}. {copyright} {ital 1997} {ital The American Physical Society}

  18. Self-excited multifractal dynamics

    NASA Astrophysics Data System (ADS)

    Filimonov, V.; Sornette, D.

    2011-05-01

    We introduce the self-excited multifractal (SEMF) model, defined such that the amplitudes of the increments of the process are expressed as exponentials of a long memory of past increments. The principal novel feature of the model lies in the self-excitation mechanism combined with exponential nonlinearity, i.e. the explicit dependence of future values of the process on past ones. The self-excitation captures the microscopic origin of the emergent endogenous self-organization properties, such as the energy cascade in turbulent flows, the triggering of aftershocks by previous earthquakes and the "reflexive" interactions of financial markets. The SEMF process has all the standard stylized facts found in financial time series, which are robust to the specification of the parameters and the shape of the memory kernel: multifractality, heavy tails of the distribution of increments with intermediate asymptotics, zero correlation of the signed increments and long-range correlation of the squared increments, the asymmetry (called "leverage" effect) of the correlation between increments and absolute value of the increments and statistical asymmetry under time reversal.

  19. Wedding ring shaped excitation coil

    DOEpatents

    MacLennan, Donald A.; Tsai, Peter

    2001-01-01

    A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and/or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency.

  20. Synaptic Control of Motoneuronal Excitability

    PubMed Central

    Rekling, Jens C.; Funk, Gregory D.; Bayliss, Douglas A.; Dong, Xiao-Wei; Feldman, Jack L.

    2016-01-01

    Movement, the fundamental component of behavior and the principal extrinsic action of the brain, is produced when skeletal muscles contract and relax in response to patterns of action potentials generated by motoneurons. The processes that determine the firing behavior of motoneurons are therefore important in understanding the transformation of neural activity to motor behavior. Here, we review recent studies on the control of motoneuronal excitability, focusing on synaptic and cellular properties. We first present a background description of motoneurons: their development, anatomical organization, and membrane properties, both passive and active. We then describe the general anatomical organization of synaptic input to motoneurons, followed by a description of the major transmitter systems that affect motoneuronal excitability, including ligands, receptor distribution, pre- and postsynaptic actions, signal transduction, and functional role. Glutamate is the main excitatory, and GABA and glycine are the main inhibitory transmitters acting through ionotropic receptors. These amino acids signal the principal motor commands from peripheral, spinal, and supraspinal structures. Amines, such as serotonin and norepinephrine, and neuropeptides, as well as the glutamate and GABA acting at metabotropic receptors, modulate motoneuronal excitability through pre- and postsynaptic actions. Acting principally via second messenger systems, their actions converge on common effectors, e.g., leak K+ current, cationic inward current, hyperpolarization-activated inward current, Ca2+ channels, or presynaptic release processes. Together, these numerous inputs mediate and modify incoming motor commands, ultimately generating the coordinated firing patterns that underlie muscle contractions during motor behavior. PMID:10747207

  1. Electronic excitations in Guanine quadruplexes.

    PubMed

    Changenet-Barret, Pascale; Hua, Ying; Markovitsi, Dimitra

    2015-01-01

    Guanine rich DNA strands, such as those encountered at the extremities of human chromosomes, have the ability to form four-stranded structures (G-quadruplexes) whose building blocks are guanine tetrads. G-quadruplex structures are intensively studied in respect of their biological role, as targets for anticancer therapy and, more recently, of their potential applications in the field of molecular electronics. Here we focus on their electronic excited states which are compared to those of non-interacting mono-nucleotides and those of single and double stranded structures. Particular emphasis is given to excited state relaxation processes studied by time-resolved fluorescence spectroscopy from femtosecond to nanosecond time scales. They include ultrafast energy transfer and trapping of ππ* excitations by charge transfer states. The effect of various structural parameters, such as the nature of the metal cations located in the central cavity of G-quadruplexes, the number of tetrads or the conformation of the constitutive single strands, are examined. PMID:24563011

  2. Channelopathies of skeletal muscle excitability.

    PubMed

    Cannon, Stephen C

    2015-04-01

    Familial disorders of skeletal muscle excitability were initially described early in the last century and are now known to be caused by mutations of voltage-gated ion channels. The clinical manifestations are often striking, with an inability to relax after voluntary contraction (myotonia) or transient attacks of severe weakness (periodic paralysis). An essential feature of these disorders is fluctuation of symptoms that are strongly impacted by environmental triggers such as exercise, temperature, or serum K(+) levels. These phenomena have intrigued physiologists for decades, and in the past 25 years the molecular lesions underlying these disorders have been identified and mechanistic studies are providing insights for therapeutic strategies of disease modification. These familial disorders of muscle fiber excitability are "channelopathies" caused by mutations of a chloride channel (ClC-1), sodium channel (NaV1.4), calcium channel (CaV1.1), and several potassium channels (Kir2.1, Kir2.6, and Kir3.4). This review provides a synthesis of the mechanistic connections between functional defects of mutant ion channels, their impact on muscle excitability, how these changes cause clinical phenotypes, and approaches toward therapeutics. PMID:25880512

  3. Elastic Electron Scattering by Ground and Laser-Excited Sodium

    NASA Astrophysics Data System (ADS)

    Ying, C. H.; Wei, H.; Wang, Y.; Vukovi?, L.

    1997-10-01

    The importance of electron collision processes involving excited species for plasma diagnostics was recognized recently.(T. Fujimoto, et al.,) National Institute for Fusion Science Report NIFS-Data-16, Nagoya, Japan, April 1992.^,(S. A. Kazantsev, Sov. Phys. Usp. 26), 328 (1983). For the alignment of the excited particles and relation with linear polarization of subsequently emitted radiation, the electron distribution function has to be retained in the expansion. We will present experimental results of low energy electron elastic scattering with ground and laser-excited sodium. From these studies, we extracted differential scattering cross sections and parameters for elastic scattering by excited sodium prepared with circularly and linearly polarized laser light. Measurements were carried out at electron impact energies 1 to 10 eV and scattering angles up to 50^o. Our previous superelastic measurements(T. Y. Jiang, Z. Shi, C. H. Ying, L. Vu)kovi?, and B. Bedreson, Phys. Rev. A 51, 3773 (1995). were used in evaluation of the present work. Data will be compared with convergent-close-coupling(I. Bray, D. V. Fursa, and I. E. McCarthy, Phys. Rev. A 49), 2667 (1994). and R-matrix-based close-coupling(B. L. Whitten, et al.,) Bull. Am. Phys. Soc. 39, 1073 (1994). calculations.

  4. Spurious Excitations in Semiclassical Scattering Theory.

    ERIC Educational Resources Information Center

    Gross, D. H. E.; And Others

    1980-01-01

    Shows how through proper handling of the nonuniform motion of semiclassical coordinates spurious excitation terms are eliminated. An application to the problem of nuclear Coulomb excitation is presented as an example. (HM)

  5. Be/X-Ray Pulsar Binary Science with LOFT

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2011-01-01

    Accretion disks are ubiquitous in astronomical sources. Accretion powered pulsars are a good test bed for accretion disk physics, because unlike for other objects, the spin of the neutron star is directly observable allowing us to see the effects of angular momentum transfer onto the pulsar. The combination of a sensitive wide-field monitor and the large area detector on LOFT will enable new detailed studies of accretion powered pulsars which I will review. RXTE observations have shown an unusually high number of Be/X-ray pulsar binaries in the SMC. Unlike binaries in the Milky Way, these systems are all at the same distance, allowing detailed population studies using the sensitive LOFT WFM, potentially providing connections to star formation episodes. For Galactic accreting pulsar systems, LOFT will allow measurement of spectral variations within individual pulses, mapping the accretion column in detail for the first time. LOFT will also provide better constraints on magnetic fields in accreting pulsars, allowing measurements of cyclotron features, observations of transitions into the centrifugal inhibition regime, and monitoring of spin-up rate vs flux correlations. Coordinated multi-wavelength observations are crucial to extracting the best science from LOFT from these and numerous other objects.

  6. Electron excitations in two-dimensional buckled honeycomb lattices

    NASA Astrophysics Data System (ADS)

    Shih, Po-Hsin; Chiu, Yu-Huang; Lin, Min-Fa

    2015-03-01

    The two-dimensional buckled honeycomb lattices system exhibits the rich Coulomb excitation spectra, being dominated by the free carrier density, band structure, and transferred momentum (q). There are two kinds of plasmon peaks in the energy loss spectra, calculated from the random phase approximation. They are, respectively, revealed at low and middle frequencies. The former, which arises from the free carriers, belongs to acoustic mode. It's frequency depends on ?{ q} at long wavelength limit. On the other hand, the latter is due to all the ?-electronic collective excitations is an optical mode. Whether such plasmon can service is mainly determined by q. The frequencies and intensities of plasmon modes are very different among graphene, silicene, germanene, and Tin. Thanks the Ministry of Science and Technology of Taiwan (ROC) for funding support.

  7. Capillary electrophoresis based on continuous-wave multiphoton excitation fluorescence

    NASA Astrophysics Data System (ADS)

    Chen, Sheng; Luo, Qingming; Zeng, Shaoqun; Chen, Tongsheng; Gong, Hui; Fu, Ling

    2003-12-01

    High performance capillary electrophoresis(HPCE) has been widely applied to the field of chemistry and life science for its advantages of high separation efficiency, short analysis times and low sample volume requirements. But how to improve the detection capability of capillary electrophoresis was ever a key problem. Multi-photon excitation (MPE) fluorescence detection could solve this problem, however this method needed expensive femtosecond mod-locked laser, which restricted the improvement of capillary electrophoresis. In this paper, we implemented a set of MPE-CE system based on a continuous wave (CW), successfully exploited the CW multi-photon excitation to achieve detection of capillary electrophoresis. In our current MPE-CE system we used Ti:sapphire laser to prove MPE-CE could work in CW mode. From this point, we would substitute the laser with laser diode (LD) in future. This is really a new but also practical idea in MPE-CE system based on CW.

  8. Band Excitation in Scanning Probe Microscopy: Sines of Change

    SciTech Connect

    Jesse, Stephen; Kalinin, Sergei V

    2011-01-01

    In three decades since Scanning Probe Microscopy (SPM) methods have entered scientific arena, they have become one of the main tool of nanoscale science and technology by offering the capability for imaging topography, magnetic, electrical, and mechanical properties on the nanometer scale. The vast majority of force-based SPM techniques to date are based on single-frequency sinusoidal excitation and detection. Here, we illustrate the intrinsic limitations of single-frequency detection that stem from the fundamental physics of dynamic systems. Consequently, many aspects of nanoscale materials functionality including quantitative mechanical, magnetic, and electrical measurements, probing dissipative interactions, to name a few remain unexplored. Band excitation is illustrated as a universal alternative to traditional single-frequency techniques that allows quantitative and reliable studies of dissipative and conservative phenomena, and can be universally applied to all ambient and liquid SPM methods.

  9. 46 CFR 111.12-3 - Excitation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (incorporated by reference; see 46 CFR 110.10-1), except that those for mobile offshore drilling units must meet... 46 CFR 110.10-1). In particular, no static exciter may be used for excitation of an emergency generator unless it is provided with a permanent magnet or a residual-magnetism-type exciter that has...

  10. 46 CFR 111.12-3 - Excitation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (incorporated by reference; see 46 CFR 110.10-1), except that those for mobile offshore drilling units must meet... 46 CFR 110.10-1). In particular, no static exciter may be used for excitation of an emergency generator unless it is provided with a permanent magnet or a residual-magnetism-type exciter that has...

  11. Resource Paper: Molecular Excited State Relaxation Processes.

    ERIC Educational Resources Information Center

    Rhodes, William

    1979-01-01

    Develops the concept of oscillatory v dissipative limits as it applies to electronic excited state processes in molecular systems. Main emphasis is placed on the radiative and nonradiative dynamics of the excited state of a molecule prepared by interaction with light or some other excitation source. (BT)

  12. Simple Science

    ERIC Educational Resources Information Center

    Cowens, John

    2006-01-01

    This brief article presents some quick and easy science experiments for those dreary winter days when classrooms need a pick-me-up. These seemingly easy science experiments will make a lasting impact on students.

  13. Forensic Science

    ERIC Educational Resources Information Center

    Berry, Keith O.; Nigh, W. G.

    1973-01-01

    A course is described, which was given during an interim, with an enrollment of 41 students. The course involved an in-depth study of forensic science, involving students with the methodology of science. (DF)

  14. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1990

    1990-01-01

    Presented are 29 science activities for secondary school science instruction. Topic areas include botany, genetics, biochemistry, anatomy, entomology, molecular structure, spreadsheets, chemistry, mechanics, astronomy, relativity, aeronautics, instrumentation, electrostatics, quantum mechanics, and laboratory interfacing. (CW)

  15. Science Sleuths.

    ERIC Educational Resources Information Center

    Lilly, Sherril L.

    1989-01-01

    Describes a two-day forensic science course that is offered to eighth grade students enrolled in Science, Mathematics, and Technology Magnet Schools. Provides sample student activity sheets for the course. (Author/RT)

  16. Science Scope.

    ERIC Educational Resources Information Center

    Stone, Richard, Ed.

    1995-01-01

    Discusses an education project launched by the National Academy of Sciences and the Pentagon to turn laid-off aerospace engineers into science teachers at Los Angeles middle schools and high schools. (MKR)

  17. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1990

    1990-01-01

    Presented are 27 science activities for secondary school science instruction. Topic areas include microbiology, botany, biochemistry, genetics, safety, earthquakes, problem solving, electricity, heat, solutions, mechanics, quantum mechanics, flame tests, and molecular structure. (CW)

  18. Inclusion, Disabilities, and Informal Science Learning. A CAISE Inquiry Group Report

    ERIC Educational Resources Information Center

    Reich, Christine; Price, Jeremy; Rubin, Ellen; Steiner, Mary Ann

    2010-01-01

    Informal science education (ISE) experiences can provide powerful opportunities for people with disabilities to experience and learn about science. When designed to be inclusive, such experiences can lead people with disabilities to feel competent and empowered as science learners, generate excitement and enthusiasm for science, and be equitable

  19. Dramatic Science

    ERIC Educational Resources Information Center

    McGregor, Debbie; Precious, Wendy

    2010-01-01

    The setting: the science classroom. The characters: you and your students. The scene: Your students acting out scientific discoveries, modeling a frog's life cycle, mimicking the transition from liquid to solid. This is "dramatic science", a teaching approach that uses acting techniques to explore and develop young children's ideas about science.…

  20. Science Lessons.

    ERIC Educational Resources Information Center

    Black, Susan

    1999-01-01

    Science teachers say that improving science education requires smaller classes, adequate resources, better staff development, and more teacher collaboration. Poor achievement on the Third International Mathematics and Science Study stems from watered-down curricula, teacher knowledge gaps, and student failures in "gate-keeping" courses. Standards

  1. Sublime Science

    ERIC Educational Resources Information Center

    Girod, Mark

    2007-01-01

    One of the shortcomings in most efforts to integrate art and science is that many people have a shallow understanding of art, which inevitably leads to shallow connections between art and science. Coloring drawings of planets, building sculptures of volcanoes, and decorating scientific diagrams are fine activities, but they do not link science and

  2. Dramatic Science

    ERIC Educational Resources Information Center

    McGregor, Debbie; Precious, Wendy

    2010-01-01

    The setting: the science classroom. The characters: you and your students. The scene: Your students acting out scientific discoveries, modeling a frog's life cycle, mimicking the transition from liquid to solid. This is "dramatic science", a teaching approach that uses acting techniques to explore and develop young children's ideas about science.

  3. Safer Science

    ERIC Educational Resources Information Center

    Roy, Ken

    2011-01-01

    This column provides best safety practices for the science classroom and laboratory. In this month's issue, pregnancy policy in the laboratory is discussed. One can't ignore the fact that student and faculty pregnancies--and the resulting potential hazards in the science laboratory--exist at the high school level. Science teachers need to be

  4. Safer Science

    ERIC Educational Resources Information Center

    Roy, Ken

    2011-01-01

    This column provides best safety practices for the science classroom and laboratory. In this month's issue, pregnancy policy in the laboratory is discussed. One can't ignore the fact that student and faculty pregnancies--and the resulting potential hazards in the science laboratory--exist at the high school level. Science teachers need to be…

  5. Watershed Science.

    ERIC Educational Resources Information Center

    Green, Tom

    1996-01-01

    Presents activities from an interdisciplinary project studying local watersheds that incorporate a broad spectrum of disciplines including science, math, geography, English, computer science, and political science. Enables students to understand how precipitation changes chemically as it interacts with the soils and human-altered landscape as it…

  6. Science First.

    ERIC Educational Resources Information Center

    Strycker, Jan Adkins

    1995-01-01

    Describes a teacher's efforts to put science first in the classroom. Discusses changing the place of science on the schedule and presents an activity to engage student interest. Concludes that a difference in teacher attitude towards science motivates students to learn. (NB)

  7. Science Facilities.

    ERIC Educational Resources Information Center

    Butin, Dan

    This paper discusses the components of key spaces found within elementary and secondary school science facilities, and highlights the common design features that facilitate quality science instruction in these areas. Three educational trends that have shaped today's school science education are also examined. Common design features highlighted

  8. Science Facilities

    ERIC Educational Resources Information Center

    Butin, Dan W.; Biehle, James T.; Motz, LaMoine L.; West, Sandra S.

    2009-01-01

    The National Research Council's "National Science Education Standards" call for science education to be "developmentally appropriate, interesting, and relevant to students' lives, emphasize student understanding through inquiry, and be connected with other school subjects." This description captures the three major trends in science education

  9. Turbulent swirling jets with excitation

    NASA Technical Reports Server (NTRS)

    Taghavi, Rahmat; Farokhi, Saeed

    1988-01-01

    An existing cold-jet facility at NASA Lewis Research Center was modified to produce swirling flows with controllable initial tangential velocity distribution. Two extreme swirl profiles, i.e., one with solid-body rotation and the other predominated by a free-vortex distribution, were produced at identical swirl number of 0.48. Mean centerline velocity decay characteristics of the solid-body rotation jet flow exhibited classical decay features of a swirling jet with S - 0.48 reported in the literature. However, the predominantly free-vortex distribution case was on the verge of vortex breakdown, a phenomenon associated with the rotating flows of significantly higher swirl numbers, i.e., S sub crit greater than or equal to 0.06. This remarkable result leads to the conclusion that the integrated swirl effect, reflected in the swirl number, is inadequate in describing the mean swirling jet behavior in the near field. The relative size (i.e., diameter) of the vortex core emerging from the nozzle and the corresponding tangential velocity distribution are also controlling factors. Excitability of swirling jets is also investigated by exciting a flow with a swirl number of 0.35 by plane acoustic waves at a constant sound pressure level and at various frequencies. It is observed that the cold swirling jet is excitable by plane waves, and that the instability waves grow about 50 percent less in peak r.m.s. amplitude and saturate further upstream compared to corresponding waves in a jet without swirl having the same axial mass flux. The preferred Strouhal number based on the mass-averaged axial velocity and nozzle exit diameter for both swirling and nonswirling flows is 0.4.

  10. Multiarmed Spirals in Excitable Media

    NASA Astrophysics Data System (ADS)

    Vasiev, Bakthier; Siegert, Florian; Weijer, Cornelis

    1997-03-01

    Numerical studies of the properties of multiarmed spirals show that they can form spontaneously in low excitability media. The maximum number of arms in a multiarmed spiral is proportional to the ratio of the single spiral period to the refractoriness of the medium. Multiarmed spirals are formed due to attraction of single spirals if these spirals rotate in the same direction and their tips are less than one wavelength apart, i.e., a spiral broken not far from its tip can evolve into a 2-armed spiral. We propose this mechanism to be responsible for the formation of multiarmed spirals in mounds of the slime mold Dictyostelium discoideum.

  11. High Frequency Chandler Wobble Excitation

    NASA Astrophysics Data System (ADS)

    Seitz, F.; Stuck, J.; Thomas, M.

    2003-04-01

    Variations of Earth rotation on sub-daily to secular timescales are caused by mass redistributions in the Earth system as a consequence of geophysical processes and gravitational influences. Forced oscillations of polar motion are superposed by free oscillations of the Earth, i.e. the Chandler wobble and the free core nutation. In order to study the interactions between externally induced polar motion and the Earth's free oscillations, a non-linear gyroscopic model has been developed. In most of the former investigations on polar motion, the Chandler wobble is introduced as a damped oscillation with predetermined frequency and amplitude. However, as the effect of rotational deformation is a backcoupling mechanism of polar motion on the Earth's rotational dynamics, both period and amplitude of the Chandler wobble are time-dependent when regarding additional excitations from, e.g., atmospheric or oceanic mass redistributions. The gyroscopic model is free of any explicit information concerning amplitude, phase, and period of free oscillations. The characteristics of the Earth's free oscillation is reproduced by the model from rheological and geometrical parameters and rotational deformation is taken into account. This enables to study the time variable Chandler oscillation when the gyro is forced with atmospheric and oceanic angular momentum from the global atmospheric ECHAM3-T21 general circulation model together with the ocean model for circulation and tides OMCT driven by ECHAM including surface pressure. Besides, mass redistributions in the Earth's body due to gravitational and loading deformations are regarded and external torques exerted by Moon and Sun are considered. The numerical results of the gyro are significantly related with the geodetically observed time series of polar motion published by the IERS. It is shown that the consistent excitation is capable to counteract the damping and thus to maintain the Chandler amplitude. Spectral analyses of the ECHAM and OMCT forcing fields give no hint for increased excitation power in the Chandler band. Thus it is assumed, that continuous high frequency excitation due to stochastic weather phenomena is responsible for the perpetuation of the Chandler wobble.

  12. Nuclear excitations at constant temperature

    NASA Astrophysics Data System (ADS)

    Voinov, A. V.; Oginni, B. M.; Grimes, S. M.; Brune, C. R.; Guttormsen, M.; Larsen, A. C.; Massey, T. N.; Schiller, A.; Siem, S.

    2009-03-01

    Neutron and proton evaporation spectra from the Li6+Mn55 and d+Co59 reactions have been analyzed with the Hauser-Feshbach approach using different input models for nuclear level densities of Ni60 and Co60 nuclei. It has been found that models with a Fermi-gas like temperature dependence fail to reproduce particle spectra from both reactions simultaneously. We obtained the surprising result that the only way to describe our data is to assume the independence of the nuclear temperature on the excitation energy up to about the 20 MeV energy range.

  13. Electron impact excitation of methane

    NASA Technical Reports Server (NTRS)

    Vuskovic, L.; Trajmar, S.

    1983-01-01

    A crossed molecular beam-electron beam apparatus was employed to examine the excitation cross-sections of CH4. Attention was given to 20, 30, and 200 eV impact energies at angles from 8-130 deg. Spectra were obtained in the elastic and inelastic realms as well as in the ionization continuum in the 12.99-15.0 eV energy-loss range. Differential cross-sections were also determined. The results are useful for modeling the behavior of CH4 in planetary atmospheres.

  14. Peculiarities of collisional excitation transfer with excited screened energy levels of atoms

    SciTech Connect

    Gerasimov, V. A.; Gerasimov, V. V.; Pavlinskiy, A. V.

    2007-09-15

    We report an experimental discovery of deviations from the known regularities in collisional excitation transfer processes for metal atoms. The collisional excitation transfer with excited screened energy levels of thulium and dysprosium atoms is studied. The selecting role of the screening 6s shell in collisional excitation transfer is shown.

  15. Theoretical studies of electronically excited states

    NASA Astrophysics Data System (ADS)

    Besley, Nicholas A.

    2014-10-01

    Time-dependent density functional theory is the most widely used quantum chemical method for studying molecules in electronically excited states. However, excited states can also be computed within Kohn-Sham density functional theory by exploitingmethods that converge the self-consistent field equations to give excited state solutions. The usefulness of single reference self-consistent field based approaches for studying excited states is demonstrated by considering the calculation of several types of spectroscopy including the infrared spectroscopy of molecules in an electronically excited state, the rovibrational spectrum of the NO-Ar complex, core electron binding energies and the emission spectroscopy of BODIPY in water.

  16. Excitation of surface electromagnetic waves on water.

    PubMed

    Singh, A K; Goben, C A; Davarpanah, M; Boone, J L

    1978-11-01

    Excitation of surface electromagnetic waves (SEW) on water was studied using optical coupling techniques at microwave frequencies. Excitation of SEW was also achieved using direct horn antenna coupling. The transmitted SEW power was increased by adding acid and salt to water. The horn antenna gave the maximum excitation efficiency 70%. It was increased to 75% by collimating the electromagnetic beam in the vertical direction. Excitation efficiency for the prism (0 degrees pitch angle) and grating couplers were 15.2% and 10.5% respectively. By changing the prism coupler pitch angle to +36 degrees , its excitation efficiency was increased to 82%. PMID:20204001

  17. Theoretical studies of electronically excited states

    SciTech Connect

    Besley, Nicholas A.

    2014-10-06

    Time-dependent density functional theory is the most widely used quantum chemical method for studying molecules in electronically excited states. However, excited states can also be computed within Kohn-Sham density functional theory by exploiting methods that converge the self-consistent field equations to give excited state solutions. The usefulness of single reference self-consistent field based approaches for studying excited states is demonstrated by considering the calculation of several types of spectroscopy including the infrared spectroscopy of molecules in an electronically excited state, the rovibrational spectrum of the NO-Ar complex, core electron binding energies and the emission spectroscopy of BODIPY in water.

  18. HEASARC - The High Energy Astrophysics Science Archive Research Center

    NASA Technical Reports Server (NTRS)

    Smale, Alan P.

    2011-01-01

    The High Energy Astrophysics Science Archive Research Center (HEASARC) is NASA's archive for high-energy astrophysics and cosmic microwave background (CMB) data, supporting the broad science goals of NASA's Physics of the Cosmos theme. It provides vital scientific infrastructure to the community by standardizing science data formats and analysis programs, providing open access to NASA resources, and implementing powerful archive interfaces. Over the next five years the HEASARC will ingest observations from up to 12 operating missions, while serving data from these and over 30 archival missions to the community. The HEASARC archive presently contains over 37 TB of data, and will contain over 60 TB by the end of 2014. The HEASARC continues to secure major cost savings for NASA missions, providing a reusable mission-independent framework for reducing, analyzing, and archiving data. This approach was recognized in the NRC Portals to the Universe report (2007) as one of the HEASARC's great strengths. This poster describes the past and current activities of the HEASARC and our anticipated developments in coming years. These include preparations to support upcoming high energy missions (NuSTAR, Astro-H, GEMS) and ground-based and sub-orbital CMB experiments, as well as continued support of missions currently operating (Chandra, Fermi, RXTE, Suzaku, Swift, XMM-Newton and INTEGRAL). In 2012 the HEASARC (which now includes LAMBDA) will support the final nine-year WMAP data release. The HEASARC is also upgrading its archive querying and retrieval software with the new Xamin system in early release - and building on opportunities afforded by the growth of the Virtual Observatory and recent developments in virtual environments and cloud computing.

  19. Exciting Times Call for Collaboration

    ERIC Educational Resources Information Center

    Jensen, Eric P.

    2008-01-01

    Brain science already has much to contribute to education and will become even more important in the future. Brain research is not going away; it is increasing and will continue to do so. As such, educators need better tools to deal with it. In this article, the author argues that educators desperately need new understandings, new ways to think…

  20. Exciting Times Call for Collaboration

    ERIC Educational Resources Information Center

    Jensen, Eric P.

    2008-01-01

    Brain science already has much to contribute to education and will become even more important in the future. Brain research is not going away; it is increasing and will continue to do so. As such, educators need better tools to deal with it. In this article, the author argues that educators desperately need new understandings, new ways to think

  1. Communicating Science through Exhibitions

    NASA Astrophysics Data System (ADS)

    Dusenbery, Paul

    2005-04-01

    It is critically important for the public to better understand the scientific process. Museum exhibitions are an important part of informal science education that can effectively reach public audiences as well as school groups. They provide an important gateway for the public to learn about compelling scientific endeavors. Science exhibitions also provide a marvelous opportunity for scientists to become engaged in the exhibit development process. The Space Science Institute (SSI) is a national leader in producing traveling science exhibitions and their associated educational programming (i.e. interactive websites, educator workshops, public talks, instructional materials). The focus of this presentation will be on two of its exhibit projects: MarsQuest (on tour for four years) and Alien Earths (its tour began early in 2005). MarsQuest is enabling millions of Americans to share in the excitement of the scientific exploration of Mars and to learn more about their own planet in the process. Alien Earths will bring origins-related research and discoveries to students and the American public. It has four interrelated exhibit areas: Our Place in Space, Star Birth, Planet Quest, and Search for Life. Exhibit visitors will explore the awesome events surrounding the birth of stars and planets; they will join scientists in the hunt for planets outside our solar system including those that may be in ``habitable zones'' around other stars; and finally they will be able to learn about how scientists are looking for signs of life beyond Earth. SSI is also developing interactive web sites based on exhibit themes. New technologies are transforming the Web from a static medium to an interactive environment with tremendous potential for informal education and inquiry-based investigations. This talk will focus on the role informal science projects play in effectively communicating science to a broad, public audience.

  2. Wavelet excited measurement of system transfer function

    NASA Astrophysics Data System (ADS)

    Olkkonen, H.; Olkkonen, J. T.

    2007-02-01

    This article introduces a new method, which is referred to as the wavelet excitation method (WEM), for the measurement of the system transfer function. Instead of commonly used impulse or sine wave excitations, the method uses a sequential excitation by biorthogonal symmetric wavelets. The system transfer function is reconstructed from the output measurements. In the WEM the signals can be designed so that if N different excitation sequences are used and the excitation rate is f, the sampling rate of the analog-to-digital converter can be reduced to f /N. The WEM is especially advantageous in testing systems, where high quality impulse excitation cannot be applied. The WEM gave consistent results in transfer function measurements of various multistage amplifiers with the linear circuit analysis (SPICE) and the sine wave excitation methods. The WEM makes available new high speed sensor applications, where the sampling rate of the sensor may be considerably lower compared with the system bandwidth.

  3. Wavelet excited measurement of system transfer function.

    PubMed

    Olkkonen, H; Olkkonen, J T

    2007-02-01

    This article introduces a new method, which is referred to as the wavelet excitation method (WEM), for the measurement of the system transfer function. Instead of commonly used impulse or sine wave excitations, the method uses a sequential excitation by biorthogonal symmetric wavelets. The system transfer function is reconstructed from the output measurements. In the WEM the signals can be designed so that if N different excitation sequences are used and the excitation rate is f, the sampling rate of the analog-to-digital converter can be reduced to f/N. The WEM is especially advantageous in testing systems, where high quality impulse excitation cannot be applied. The WEM gave consistent results in transfer function measurements of various multistage amplifiers with the linear circuit analysis (SPICE) and the sine wave excitation methods. The WEM makes available new high speed sensor applications, where the sampling rate of the sensor may be considerably lower compared with the system bandwidth. PMID:17578145

  4. Chromatic shadow compatibility and cone-excitation ratios

    NASA Astrophysics Data System (ADS)

    Heckman, Genevieve M.; Muday, Jeffrey A.; Schirillo, James A.

    2005-03-01

    Logvinenko [Perception 31, 201 (2002)] asserts that Adelson's wall-of-blocks illusion [Science 262, 2042 (1993)], where identical gray-cube surface tops appear to differ in brightness, arises when the surfaces surrounding the cube tops are shadow compatible, creating a concomitant illusion of transparency. We replicated Logvinenko's main findings in the chromatic domain across three experiments in which observers match cube tops in hue, saturation, and brightness. A second set of stimuli adjusted cone-excitation ratios across the apparent transparency border [Proc. R. Soc. London 257, 115 (1994)], which enhanced lightness and brightness constancy but only when the stimuli varied in both chromaticity and intensity.

  5. Bridging Science and Policy: The AGU Science Policy Conference

    NASA Astrophysics Data System (ADS)

    Hankin, E. R.; Uhlenbrock, K.; Landau, E. A.

    2013-12-01

    In recent years, science has become inextricably linked to the political process. As such, it is more important now than ever for science to forge a better relationship with politics, for the health of both science and society. To help meet this need, the American Geophysical Union (AGU) strives to engage its members, shape policy, and inform society about the excitement of Earth and space science and its role in developing solutions for the sustainability of the planet. In June 2013, AGU held its second annual Science Policy Conference in Washington, D.C. The goal of the conference is to provide a new forum for diverse discussions and viewpoints on the challenges and opportunities of science policy, with a focus on applications of Earth and space science that serve local, national, and international communities. The meeting brought together more than 300 scientists, policy makers, industry professionals, members of the press, and other stakeholders to discuss the topics concerning the Arctic, climate change, oceans, energy, technology and infrastructure, and natural hazards science as they relate to challenges impacting society. Sessions such as 'The Water-Energy Nexus,' 'Potential for Megadisasters,' 'The Changing Ocean and Impacts on Human Health,' and 'Drowning and Drought: Agricultural Impacts of Climate Change' are examples of some of the intriguing and timely science policy issues addressed at the conference. The findings from the conference were used to develop a summary report. The report highlights key facts and figures to be used as a resource in discussions with policy makers and other stakeholders regarding the conference topics. This presentation will discuss the goals and outcomes of the conference and how the event represents one of the many ways AGU is approaching its 'Science and Society' priority objective as part of the Union's strategic plan; namely by increasing the effectiveness and recognition of AGU among policy makers as an authoritative source of integrated, interdisciplinary Earth and space science information.

  6. Science Squared: Teaching Science Visually.

    ERIC Educational Resources Information Center

    Paradis, Olga; Savage, Karen; Judice, Michelle

    This paper describes a collection of novel ideas for bulletin board displays that would be useful in supplementing science classroom instruction. Information on women and minorities in science; science concepts in everyday activities such as nutrition, baseball, and ice cream-making; and various holidays and celebratory events is included. Each…

  7. Science Squared: Teaching Science Visually.

    ERIC Educational Resources Information Center

    Paradis, Olga; Savage, Karen; Judice, Michelle

    This paper describes a collection of novel ideas for bulletin board displays that would be useful in supplementing science classroom instruction. Information on women and minorities in science; science concepts in everyday activities such as nutrition, baseball, and ice cream-making; and various holidays and celebratory events is included. Each

  8. Formation of excited neutral D* fragments from D2 by a strong laser field

    NASA Astrophysics Data System (ADS)

    Berry, Ben; Zohrabi, M.; Jochim, Bethany; Severt, T.; Ablikim, U.; Hayes, D.; Rajput, Jyoti; Kanaka Raju, P.; Feizollah, Peyman; Carnes, K. D.; Esry, B. D.; Ben-Itzhak, I.

    2015-05-01

    Excited neutral D* fragments from D2 are produced by intense, ultra-short laser pulses (5-85 fs). The kinetic energy release (KER) upon fragmentation is found to be very sensitive to laser parameters such as chirp, peak intensity, and pulse duration. Furthermore, using field ionization of highly excited D* fragments, we are able to determine the n population in a range of excited states (17 <= n <= 44). Due to the long flight time to the detector (tens of ?s), much of the initial excited population decays by spontaneous emission. We simulate this process in order to link the measured population to that created by the laser. On the technical side, we also present a scheme for determining the detection efficiency of an MCP detector for excited neutral atoms. This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. BJ is also supported by DOE-SCGF (DE-AC05-06OR23100).

  9. Astronomical Approach to Physical Science Curriculum

    NASA Astrophysics Data System (ADS)

    Manning, H. L. K.; Churukian, A. D.

    2004-11-01

    The Astronomical Approach to Physical Science Curriculum (AAPS Curriculum) is an innovative curriculum that incorporates an astronomy theme into an inquiry-based physical science curriculum for pre-service, elementary school teachers. Many physical science courses are a non-cohesive collection of topics required for the state teaching license. Through the use of astronomy and space science examples, the AAPS Curriculum will have a coherent theme that ties the wide variety of physical science topics together and provides many real world applications for the topics covered in the course. This new curriculum will incorporate the applications of knowledge to complete the learning cycle-exploration, concept introduction, application. Astronomy and space science applications will be emphasized throughout the curriculum. The theme of astronomy was chosen to prepare elementary school teachers for teaching astronomy and space science in their classroom, as this is a topic in which many school children are consistently interested. Since astronomy is a topic that can be used as a springboard to teach many other areas of study, we want teachers who are knowledgeable in topics of astronomy so they are capable of preparing creative lessons throughout their entire curriculum that are exciting to their students. The AAPS Curriculum will train college students to become teachers who are comfortable with physical science and astronomy topics and who are excited to teach these topics in their classroom. Funding for this work is provided by the IDEAS grant program of the Space Telescope Science Institute.

  10. Laser-based excitation and diagnostics of planar fractures

    NASA Astrophysics Data System (ADS)

    Blum, T. E.; Van Wijk, K.; Snieder, R.; Willis, M. E.

    2011-12-01

    Faults are of interest not only to earth science, but also at different scales in the non-destructive testing (NDT) community. Remote sensing of faults is of interest to both communities, with the idea of inverting for the fracture properties in a non-invasive way. Alternatively, the wave field directly excited at the fracture is of interest to both communities because the waves thus radiated are equivalent to those emitted by acoustic emissions or micro-earthquakes. Much can be learned from recording of elastic waves excited at the the fracture. Based on technology developed for NDT, we use laser ultrasonics in the laboratory to excite and detect elastic waves, in order to determine the properties of fractures or faults in laboratory rock and synthetic samples. We show examples of wave propagation in a clear Poly(methyl methacrylate) cylinder. By focusing a high power infrared (IR) laser inside the cylinder we create a visible single disk-shaped fracture near the center of the sample. The laser generates a short pulse (~20 ns) of infrared light that is absorbed by the sample material at the focal point and is converted into heat. The sudden thermal expansion generates stress and forms a fracture parallel to the cylindrical axis. We excite elastic waves at the surface of the sample using the same high-power pulsed laser, but at a much lower energy setting, and with an unfocused beam. We measure the direct and scattered wave field from the fracture with a laser interferometer, and also excite the fracture directly with a fraction of the source laser energy impinging directly on the fracture. A comparison of the direct excitation and the elastic scattered wavefields, including studies of the tip diffractions from the fracture, shows strong agreement. The measured tip diffractions carry information about the stress concentration near the crack tips, which is crucial for understanding rupture processes. This novel laboratory technique allows us to measure the source radiation pattern under various conditions, and opens new possibilities for understanding earthquake dynamics and fracture dynamics, as a function of stress loads, local excitation of the fracture, and fluid content of fractures.

  11. Multiphoton excitation of fluorescent DNA base analogs.

    PubMed

    Katilius, Evaldas; Woodbury, Neal W

    2006-01-01

    Multiphoton excitation was used to investigate properties of the fluorescent DNA base analogs, 2-aminopurine (2AP) and 6-methylisoxanthopterin (6MI). 2-aminopurine, a fluorescent analog of adenine, was excited by three-photon absorption. Fluorescence correlation measurements were attempted to evaluate the feasibility of using three-photon excitation of 2AP for DNA-protein interaction studies. However, high excitation power and long integration times needed to acquire high signal-to-noise fluorescence correlation curves render three-photon excitation FCS of 2AP not very useful for studying DNA base dynamics. The fluorescence properties of 6-methylisoxanthopterin, a guanine analog, were investigated using two-photon excitation. The two-photon absorption cross-section of 6MI was estimated to be about 2.5 x 10(-50) cm(4)s (2.5 GM units) at 700 nm. The two-photon excitation spectrum was measured in the spectral region from 700 to 780 nm; in this region the shape of the two-photon excitation spectrum is very similar to the shape of single-photon excitation spectrum in the near-UV spectral region. Two-photon excitation of 6MI is suitable for fluorescence correlation measurements. Such measurements can be used to study DNA base dynamics and DNA-protein interactions over a broad range of time scales. PMID:16965161

  12. Multiphoton excitation of fluorescent DNA base analogs

    NASA Astrophysics Data System (ADS)

    Katilius, Evaldas; Woodbury, Neal W.

    2006-07-01

    Multiphoton excitation was used to investigate properties of the fluorescent DNA base analogs, 2-aminopurine (2AP) and 6-methylisoxanthopterin (6MI). 2-aminopurine, a fluorescent analog of adenine, was excited by three-photon absorption. Fluorescence correlation measurements were attempted to evaluate the feasibility of using three-photon excitation of 2AP for DNA-protein interaction studies. However, high excitation power and long integration times needed to acquire high signal-to-noise fluorescence correlation curves render three-photon excitation FCS of 2AP not very useful for studying DNA base dynamics. The fluorescence properties of 6-methylisoxanthopterin, a guanine analog, were investigated using two-photon excitation. The two-photon absorption cross-section of 6MI was estimated to be about 2.510-50 cm4s (2.5 GM units) at 700 nm. The two-photon excitation spectrum was measured in the spectral region from 700 to 780 nm; in this region the shape of the two-photon excitation spectrum is very similar to the shape of single-photon excitation spectrum in the near-UV spectral region. Two-photon excitation of 6MI is suitable for fluorescence correlation measurements. Such measurements can be used to study DNA base dynamics and DNA-protein interactions over a broad range of time scales.

  13. Earth Sciences Division annual report 1989

    SciTech Connect

    Not Available

    1990-06-01

    This Annual Report presents summaries of selected representative research activities from Lawrence Berkeley Laboratory grouped according to the principal disciplines of the Earth Sciences Division: Reservoir Engineering and Hydrology, Geology and Geochemistry, and Geophysics and Geomechanics. We are proud to be able to bring you this report, which we hope will convey not only a description of the Division's scientific activities but also a sense of the enthusiasm and excitement present today in the Earth Sciences.

  14. Collective excitations of supersymmetric plasma

    SciTech Connect

    Czajka, Alina; Mrowczynski, Stanislaw

    2011-02-15

    Collective excitations of N=1 supersymmetric electromagnetic plasma are studied. Since the Keldysh-Schwinger approach is used, not only equilibrium but also nonequilibrium plasma, which is assumed to be ultrarelativistic, is under consideration. The dispersion equations of photon, photino, electron, and selectron modes are written down and the self-energies, which enter the equations, are computed in the hard loop approximation. The self-energies are discussed in the context of effective action which is also given. The photon modes and electron ones appear to be the same as in the usual ultrarelativistic plasma of electrons, positrons, and photons. The photino modes coincide with the electron ones and the selectron modes are as of a free relativistic massive particle.

  15. Excited Baryons in Holographic QCD

    SciTech Connect

    de Teramond, Guy F.; Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins

    2011-11-08

    The light-front holographic QCD approach is used to describe baryon spectroscopy and the systematics of nucleon transition form factors. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. The transition from the hard-scattering perturbative domain to the non-perturbative region is sensitive to the detailed dynamics of confined quarks and gluons. Computations of such phenomena from first principles in QCD are clearly very challenging. The most successful theoretical approach thus far has been to quantize QCD on discrete lattices in Euclidean space-time; however, dynamical observables in Minkowski space-time, such as the time-like hadronic form factors are not amenable to Euclidean numerical lattice computations.

  16. Excitation of interstellar hydrogen chloride

    NASA Technical Reports Server (NTRS)

    Neufild, David A.; Green, Sheldon

    1994-01-01

    We have computed new rate coefficients for the collisional excitation of HCl by He, in the close-coupled formalism and using an interaction potential determined recently by Willey, Choong, & DeLucia. Results have been obtained for temperatures between 10 K and 300 K. With the use of the infinite order sudden approximation, we have derived approximate expressions of general applicability which may be used to estimate how the rate constant for a transition (J to J prime) is apportioned among the various hyperfine states F prime of the final state J prime. Using these new rate coefficients, we have obtained predictions for the HCl rotational line strengths expected from a dense clump of interstellar gas, as a function of the HCl fractional abundance. Over a wide range of HCl abundances, we have found that the line luminosities are proportional to abundance(exp 2/3), a general result which can be explained using a simple analytical approximation. Our model for the excitation of HCl within a dense molecular cloud core indicates that the J = 1 goes to 0 line strengths measured by Blake, Keene, & Phillips toward the Orion Molecular Cloud (OMC-1) imply a fractional abundance n(HCl)/n(H2) approximately 2 x 10(exp -9), a value which amounts to only approximately 0.3% of the cosmic abundance of chlorine nuclei. Given a fractional abundance of 2 x 10(exp -9), the contribution of HCl emission to the total radiative cooling of a dense clump is small. For Orion, we predict a flux approximately 10(exp -19) W/sq cm for the HCl J = 3 goes to 2 line near 159.8 micrometers, suggesting that the strength of this line could be measured using the Infrared Space Observatory.

  17. Science of Team Science Listserv - Team Science Toolkit

    Cancer.gov

    The Science of Team Science Listserv provides an open forum for all subscribers to share information relevant to the practice and study of team science. The listserv is maintained by the Science of Team Science team at the National Cancer Institute, Division of Cancer Control and Population Science, Behavioral Research Program, and the Northwestern University Clinical and Translational Sciences (NUCATS).

  18. Reading Science

    ERIC Educational Resources Information Center

    Carlson, Kenneth

    2005-01-01

    Reading the average science textbook, one is struck with a question: Why would people devote their lives to the study of a subject as dry as the Sahara Desert? Students in science classes only need to be let in on the great secret of science. It is fun and full of the stuff in page-turner novels--intrigue, mystery, romance, and sometimes just dumb

  19. Metal-enhanced fluorescence and FRET on nanohole arrays excited at angled incidence.

    PubMed

    Poirier-Richard, H-P; Couture, M; Brule, T; Masson, J-F

    2015-07-21

    The influence of experimental parameters on the performance of plasmonic sensors is of great importance in analytical sciences. The plasmon coupling conditions (angle of incidence, metal composition, laser frequency and excitation/emission properties of fluorophores) were thus investigated for surface plasmon-enhanced fluorescence on metallic nanohole arrays. Optimal fluorescence enhancements were achieved when the plasmon resonance, the excitation laser and the fluorophore's excitation wavelengths were matched. The enhancement of the acceptor emission of a rhodamine 6G(Rh6G)-Quasar670 FRET pair was achieved on the nanohole arrays by tuning the plasmon wavelength with the maximal overlap of the donor's emission and acceptor excitation. Silver nanohole arrays achieved larger fluorescence enhancement than gold nanohole arrays at 532 nm, while gold nanohole arrays led to larger fluorescence enhancement at 635 nm. These results demonstrate the importance of tuning the plasmon coupling conditions for surface plasmon-enhanced fluorescence sensing. PMID:25670087

  20. Hedgehog Excitations and their Superconducting Cores in the Antiferromagnetic State of SO(5) Materials

    NASA Astrophysics Data System (ADS)

    Goldbart, Paul M.

    1998-03-01

    Zhang's SO(5) approach to the physics of high-temperature superconducting materials(S.-C. Zhang, Science 275), 1089 (1997). contains the possibility that the antiferromagnetic state should support novel excitations that resemble antiferromagnetic hedgehogs at large distances but are predominantly superconducting inside a core region(P. M. Goldbart, Antiferromagnetic hedgehogs with superconducting cores); cond- mat/9711088 (UIUC Preprint P-97-10-030-iii).. Neither singular nor topologically stable, in contrast with their hedgehog cousins in pure antiferromagnetism, these excitations are what hedgehogs become when antiferromagnetic order is permitted to `` escape'' toward superconductivity---a central element in Zhang's approach. We describe the structure of antiferromagnetic hedgehog excitations with superconducting cores within the context of Zhang's approach to high-temperature superconducting materials, and touch upon a number of the experimental implications that these excitations engender.

  1. Near gap excitation of a CDW amplitude mode by time-resolved photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Leuenberger, Dominik; Yang, Shuolong; Sobota, Jonathan; Giraldo, Paula; Kirchmann, Patrick; Fisher, Ian; Shen, Zhi-Xun

    2014-03-01

    We present time-, angle- and energy-resolved photoelectron spectroscopy data from the light rear-earth tritelluride compound CeTe3. An in-plane Peierls distortion in the tellurium slabs leads to the formation of an incommensurate Charge Density Wave (CDW), accompanied by a CDW gap at the Fermi level. Ultrafast optical laser excitation and subsequent relaxation by means of electron-phonon coupling can coherently excite a periodic modulation of the CDW band position and the gap size in rear-earth tritellurides. In this work, the use of tuneable near infrared laser pulses allows for optical excitation slightly above and below the measured gap value of 570 meV. The smaller excitation phase space not only leads to cleaner amplitude mode signal but also helps to pin down the optical transitions, which are the driving mechanisms for the transient CDW phase transition. Financial support by the Swiss National Science Foundation is duly acknowledged.

  2. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1987

    1987-01-01

    Contains 31 activities and experiments from the biological and physical sciences. Addresses such areas as reproduction, biotechnology, ecology, proteins, nitrates, aerosols, metal crystallinity, circuit boards, and photoswitching. (ML)

  3. Propagating plasmon excitation of molecular junctions for spectroscopy

    NASA Astrophysics Data System (ADS)

    Evans, Charlotte; Zolotavin, Pavlo; Li, Yajing; Natelson, Doug

    2015-03-01

    Simultaneous measurements of inelastic electron tunneling spectra and surface-enhanced Raman spectroscopy (SERS) can provide critical information about how heat dissipates through a material at the molecular level by determining the electronic and vibrational energy distributions at the molecular scale. Gold bowtie nanostructures were fabricated to be used as SERS substrates, conventionally with exciting light incident directly on the molecular junction. Electromigrating these devices created interelectrode nanogaps with single-molecule sensitivity in which the Raman scattering rate is dominated by plasmonically enhanced electromagnetic fields due to the presence of the metal nanojunction near the molecules of interest. Adding metallic gratings to the electrode design enables the excitation of propagating plasmon modes that can couple into the junction region without direct excitation by far-field radiation. We will present preliminary data on how the addition of these gratings affects single-molecule SERS and the electrical properties of the molecules in these junctions. National Science Foundation Graduate Research Fellowship under Grant No. DGE-1450681 and ARO award W911 NF-13-1-0476

  4. Ground and Excited State Spectra of a Quantum Dot

    NASA Astrophysics Data System (ADS)

    Stewart, D. R.; Sprinzak, D.; Patel, S. R.; Marcus, C. M.; Duruoz, C. I.; Harris, J. S.

    1998-03-01

    We present linear and nonlinear magnetoconductance measurements of the ground and excited state spectra for successive electron occupancy in a gate defined lateral quantum dot. Previous measurementsfootnote D.R. Stewart, D. Sprinzak, C.M. Marcus, C.I. Duruoz and J.S. Harris Jr., Science 278, (1997). showed a direct correlation between the mth excited state of the N-electron system and the ground state of the (N+m)-electron system for m up to 4, consistent to a large degree with a single-particle picture. Here we report quantitative deviations of the excited state spectra from the spectrum of ground state magnetoconductances, attributed to many-body interactions in the finite system of N ~200 electrons. We also describe the behaviour of anticrossings in the ground state magnetoconductances. We acknowledge the support of JSEP (DAAH04-94-G-0058), ARO (DAAH04-95-1-0331), ONR-YIP (N00014-94-1-0622) and the NSF-PECASE program. D.S. acknowledges the support of MINERVA grant.

  5. Waking-up to Science!

    NASA Astrophysics Data System (ADS)

    2007-03-01

    The Science on Stage festival as an alarm clock for science teaching How is Europe to tackle its shortage of scientists? The EIROforum Science on Stage festival aims to give European teachers some of the answers they need to take up this urgent challenge. This unique event, showcasing the very best of today's science education, will feature science demonstrations, a science teaching fair with some 66 stands, and a Round Table discussion with the participation of the European Commissioner for Science and Research, Janez Potočnik. ESO PR Photo 14/07 ESO PR Photo 14/07 Science on Stage will have the city of Grenoble (France) buzzing from 2 to 6 April 2007. A rugby team and a hockey team will take on the power of the vacuum, a cook will demonstrate how science can inspire new culinary ideas, visitors will discover the real colour of the sun, an inflatable model of Borromini's gallery will help to explain the science of optical illusions, and Merlin himself will reveal all about how to make a cake float. These are just some of the exciting things that will be happening at the EIROforum Science on Stage festival. By showing how fascinating and entertaining science can be, the event aims to attract young people to science and ultimately help to reduce the shortage of scientists in Europe. With support from the European Commission, this international festival will bring together some 500 science educators from 27 European countries. The highlight of the festival will be a Round Table discussion on 'Science Education in the Age of the Knowledge Society - Strengthening Science Education in Europe', which will take place on 5 April 2007 with the participation of the European Commissioner for Science and Research, Janez Potočnik. The panellists - all high-ranking decision-makers - will include the Danish Minister for Education, Bertel Haarder, the MEP Vittorio Prodi, and the Chair of the UK's Engineering and Physical Sciences Research Council, Julia Higgins. "Curiosity is in our genes", says Potočnik. "Unfortunately it tends to die away when we grow up. This is because the ways we raise and educate our children and the ways we work and live do not always support innovative thinking and doing. We cannot change this overnight. But I think it is worth making the effort to awaken this dormant passion and initiatives like Science on Stage can be a very effective alarm clock", he adds. The festival will close with the presentation of the European Science Teaching Awards. The teaching materials and methods voted to be the best in Europe will then be presented in the 'Science in School' magazine, distributed free of charge to 30,000 teachers in Europe. The festival is the climax of a two-year programme of events organised in virtually every European country and from which delegates have been selected for their outstanding projects for promoting science. The winners of ESO's Catch a Star! 2007 contest will also be announced during the Science on Stage festival. The event follows on from the hugely successful 'Physics on Stage' and 'Science on Stage' festivals organised by EIROforum in 2000, 2002, 2003 and 2005. Journalists are cordially invited to take part in this unique European event. Practical information, including the detailed festival programme, is available on the Science on Stage web site at http://www.ill.fr/scienceonstage2007. A detailed press kit is available at http://www.ill.fr/scienceonstage2007/fichiers/SOSpresskit.pdf

  6. Search for excited neutrinos in Z decay

    NASA Astrophysics Data System (ADS)

    Decamp, D.; Deschizeaux, B.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Alemany, R.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Gaitan, V.; Garrido, Ll.; Mato, P.; Miguel, R.; Mir, Ll. M.; Orteu, S.; Pacheco, A.; Perlas, J. A.; Tubau, E.; Catanesi, M. G.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Maggi, M.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Gao, Y.; Hu, H.; Huang, D.; Jin, S.; Lin, J.; Ruan, T.; Wang, T.; Wu, W.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhao, W.; Atwood, W. B.; Bird, F.; Blucher, E.; Bonvicini, G.; Bossi, F.; Bourotte, J.; Brown, D.; Burnett, T. H.; Drevermann, H.; Dydak, F.; Forty, R. W.; Grab, C.; Hagelberg, R.; Haywood, S.; Jost, B.; Kasemann, M.; Kellner, G.; Knobloch, J.; Lacourt, A.; Lehraus, I.; Lohse, T.; Marchioro, A.; Martinez, M.; Menary, S.; Minten, A.; Miotto, A.; Nash, J.; Palazzi, P.; Ranjard, F.; Redlinger, G.; Roth, A.; Rothberg, J.; Rotscheidt, H.; von Rden, W.; St. Denis, R.; Schlatter, D.; Takashima, M.; Talby, M.; Taureg, H.; Tejessy, W.; Wachsmuth, H.; Wasserbaech, S.; Wheeler, S.; Wiedenmann, W.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Bardadin-Otwinowska, M.; Falvard, A.; El Fellous, R.; Gay, P.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Proriol, J.; Prulhire, F.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Mllerud, R.; Nilsson, B. S.; Petersen, G.; Efthymiopoulos, I.; Simopoulou, E.; Vayaki, A.; Badier, J.; Blondel, A.; Bonneaud, G.; Braems, F.; Brient, J. C.; Fouque, G.; Gamess, A.; Guirlet, R.; Rosowsky, A.; Roug, A.; Rumpf, M.; Tanaka, R.; Videau, H.; Videau, I.; Candlin, D. J.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Mermikides, M.; Sawyer, L.; Stimpfl, G.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Campana, P.; Capon, G.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Massimo-Brancacci, F.; Murtas, F.; Murtas, G. P.; Nicoletti, G.; Pepe-Altarelli, M.; Picchi, P.; Zografou, P.; Altoon, B.; Boyle, O.; Halley, A. W.; Ten Have, I.; Hearns, J. L.; Lynch, J. G.; Morton, W. T.; Raine, C.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Brandl, B.; Braun, O.; Geiges, R.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Belk, A. T.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Dornan, P. J.; Dugeay, S.; Greene, A. M.; Hassard, J. F.; Patton, S. J.; Sedgbeer, J. K.; Taylor, G.; Tomalin, I. R.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Keemer, N. R.; Nuttall, M.; Rowlingson, B. S.; Sloan, T.; Snow, S. W.; Barczewski, T.; Bauerdick, L. A. T.; Kleinknecht, K.; Renk, B.; Roehn, S.; Sander, H.-G.; Schmelling, M.; Steeg, F.; Albanese, J.-P.; Aubert, J.-J.; Benchouk, C.; Bernard, V.; Bonissent, A.; Courvoisier, D.; Etienne, F.; Papalexiou, S.; Payre, P.; Pietrzyk, B.; Qian, Z.; Blum, W.; Cattaneo, P.; Cowan, G.; Dehning, B.; Dietl, H.; Fernandez-Bosman, M.; Jahn, A.; Lange, E.; Ltjens, G.; Lutz, G.; Mnner, W.; Moser, H.-G.; Pan, Y.; Richter, R.; Schwarz, A. S.; Settles, R.; Stiegler, U.; Stierlin, U.; Thomas, J.; Bertin, V.; de Bouard, G.; Boucrot, J.; Callot, O.; Chen, X.; Cordier, A.; Davier, M.; Ganis, G.; Grivaz, J.-F.; Heusse, Ph.; Janot, P.; Journ, V.; Kim, D. W.; Lefranois, J.; Lutz, A.-M.; Veillet, J.-J.; Zhang, Z.; Zomer, F.; Amendolia, S. R.; Bagliesi, G.; Batignani, G.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Ciocci, M. A.; Ferrante, I.; Fidecaro, F.; Fo, L.; Focardi, E.; Forti, F.; Giassi, A.; Giorgi, M. A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Carter, J. M.; Green, M. G.; March, P. V.; Medcalf, T.; Saich, M. R.; Strong, J. A.; Thomas, R. M.; Wildish, T.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Edwards, M.; Fisher, S. M.; Harvey, J.; Jones, T. J.; Norton, P. R.; Salmon, D. P.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Klopfenstein, C.; Lanon, E.; Locci, E.; Loucatos, S.; Mirabito, L.; Monnier, E.; Perez, P.; Perrier, F.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Ashman, J. G.; Booth, C. N.; Combley, F.; Dinsdale, M.; Martin, J.; Parker, D.; Thompson, L. F.; Brandt, S.; Burkhardt, H.; Grupen, C.; Meinhard, H.; Neugebauer, E.; Schfer, U.; Seywerd, H.; Apollinari, G.; Giannini, G.; Gobbo, B.; Liello, F.; Milotti, E.; Rolandi, L.; Bellantoni, L.; Boudreau, J. F.; Cinabro, D.; Conway, J. S.; Cowen, D. F.; Deweerd, A. J.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Harton, J. L.; Hilgart, J.

    1990-11-01

    Excited neutrinos decaying into a neutrino and a photon are searched for in the ALEPH detector at LEP. No evidence is found for Z decay into vv ? or v ?v ? final states. Upper limits are derived on excited neutrino couplings up to excited neutrino masses close to the Z mass. Lower limits on the v ? mass, independent of the v ? decay modes, are deduced from the total Z width.

  7. Design evaluation: S-band exciters

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A design evaluation study was conducted to produce S-band exciter (SBE) system to provide a highly stable phase or modulated carrier for transmission to spacecraft. The exciter is part of an S-band receiver/exciter/ranging system at Spaceflight Tracking and Data Network (STDN) ground stations. The major features of the system are defined. Circuit diagrams of the electronic components are provided.

  8. Excitement in shame: the price we pay.

    PubMed

    Aledort, Stewart L

    2014-01-01

    This paper explores the role of excitement in shame, extending the theoretical underpinnings of my work (Aledort, 2002, 2003, 2008, 2009) on narcissism and the omnipotent child syndrome. Shame, excitement, and early narcissistic self-states are complexly intermingled, each influencing the other. Empathy alone is insufficient; the passion connected to shame can be easily hidden. Detailed case studies describe a model for working with the excitement in shame, how it functions, and how it gets resolved. PMID:24320576

  9. Excited states and photodissociation of hydroxymethyl hydroperoxide.

    PubMed

    Eisfeld, Wolfgang; Francisco, Joseph S

    2008-05-01

    The structure of hydroxymethyl hydroperoxide (HOCH(2)OOH) (HMHP) has been examined using coupled cluster and multireference configuration interaction methods to study the excited states and probable photodissociation products. The results are compared to experiments. The vertical excitation energies for several excited states of HOCH(2)OOH are presented as well as the excited state energies along the O-O, O-H, C-O, and C-H dissociation pathways. The results help in the interpretation of experimental UV absorption spectra and elucidate the photodissociation mechanism of HMHP under tropospheric conditions. PMID:18465919

  10. Generic two-variable model of excitability

    NASA Astrophysics Data System (ADS)

    Ventura, A. C.; Mindlin, G. B.; Dawson, S. Ponce

    2002-04-01

    We present a simple model that displays all classes of two-dimensional excitable regimes. One of the variables of the model displays the usual spikes observed in excitable systems. Since the model is written in terms of a ``standard'' vector field, it is always possible to fit it to experimental data displaying spikes in an algorithmic way. In fact, we use it to fit a series of membrane potential recordings obtained in the medicinal leech and time series generated with the FitzHugh-Nagumo equations and the excitability model of Egua et al. [Phys. Rev. E 58, 2636 (1998)]. In each case, we determine the excitability class of the corresponding system.

  11. Science Fairs for Science Literacy

    NASA Astrophysics Data System (ADS)

    Mackey, K. R.

    2014-12-01

    Science literacy is imperative for well informed civic and personal decision making, yet only a quarter of American adults are proficient enough in science to understand science stories reported in the popular press. Hands-on research increases confidence in and understanding of science. When guiding students in designing and conducting science fair projects, mentors can foster science literacy by helping students focus on three goals: (1) articulating hypotheses or questions, (2) designing feasible projects, and (3) learning to make and interpret graphs. These objectives introduce students to the methodological nature of scientific research and give them the tools to interpret scientific facts and data in order to make informed decisions for themselves and society.

  12. The science in social science

    PubMed Central

    Bernard, H. Russell

    2012-01-01

    A recent poll showed that most people think of science as technology and engineering—life-saving drugs, computers, space exploration, and so on. This was, in fact, the promise of the founders of modern science in the 17th century. It is less commonly understood that social and behavioral sciences have also produced technologies and engineering that dominate our everyday lives. These include polling, marketing, management, insurance, and public health programs. PMID:23213222

  13. The sciences of science communication

    PubMed Central

    Fischhoff, Baruch

    2013-01-01

    The May 2012 Sackler Colloquium on “The Science of Science Communication” brought together scientists with research to communicate and scientists whose research could facilitate that communication. The latter include decision scientists who can identify the scientific results that an audience needs to know, from among all of the scientific results that it would be nice to know; behavioral scientists who can design ways to convey those results and then evaluate the success of those attempts; and social scientists who can create the channels needed for trustworthy communications. This overview offers an introduction to these communication sciences and their roles in science-based communication programs. PMID:23942125

  14. Science Teaching to Fire the Imagination.

    ERIC Educational Resources Information Center

    Sandford, Diana; Fleetwood, Julie

    1997-01-01

    Presents a range of exciting ideas for encouraging active learning, for illuminating new concepts, and for making science lessons fun. Topics include modeling, matter, heat, diffusion, changes of state, heat transfer, energy changes, atomic structure, waves, gravity, enzymes, and habitats. (JRH)

  15. Deconstructing Science

    ERIC Educational Resources Information Center

    Trifonas, Peter Pericles

    2012-01-01

    In this paper I expand on the premises of Jesse Bazzul's thesis in his paper, "Neoliberal ideology, global capitalism, and science education: engaging the question of subjectivity," exploring the implications of the ideologies within the culturally emerging logic of science exposes the incommensurability of intents and purposes in its methods and…

  16. Science Notes.

    ERIC Educational Resources Information Center

    Murray, A. J. S.; And Others

    1988-01-01

    Presents 31 science activities for use with high school or college science classes. Topics included are: chromatography, ecology, invertebrates, enzymes, genetics, botany, creep, crystals, diffusion, computer interfaces, acid rain, teaching techniques, chemical reactions, waves, electric fields, rainbows, electricity, magnetic fields, and a Pitot…

  17. Talking Science

    ERIC Educational Resources Information Center

    Shwartz, Yael; Weizman, Ayelet; Fortus, David; Sutherland, LeeAnn; Merrit, Joi; Krajcik, Joe

    2009-01-01

    Science is a social process--one that involves particular ways of talking, reasoning, observing, analyzing, and writing, which often have meaning only when shared within the scientific community. Discussions are one of the best ways to help students learn to "talk science" and construct understanding in a social context. Since inquiry is an

  18. Soundsational Science

    ERIC Educational Resources Information Center

    Carrier, Sarah J.; Scott, Catherine Marie; Hall, Debra T.

    2012-01-01

    The science of sound helps students learn that sound is energy traveling in waves as vibrations transfer the energy through various media: solids, liquids, and gases. In addition to learning about the physical science of sound, students can learn about the sounds of different animal species: how sounds contribute to animals' survival, and how…

  19. Personalizing Science

    ERIC Educational Resources Information Center

    Danielowich, Robert M.

    2014-01-01

    Science teachers are aware of many social issues that intersect with science. These socio-scientific issues (SSIs) are "open-ended problems without clear-cut solutions [that] can be informed by scientific principles, theories, and data, but…cannot be fully determined by [them]" (Sadler 2011, p. 4). This article describes the SSI lessons…

  20. Why Science?

    ERIC Educational Resources Information Center

    Primary Science Review, 2006

    2006-01-01

    This article presents people from many walks of life, including some well-known names, who share their views about science. Adam Hart-Davis, who studied chemistry at university and is now an author, photographer, historian and broadcaster, explains why science cannot start too soon. Lis Nairn, Manager, Stratigraphy, with Fugro Robertson Ltd (Oil

  1. Science Alive!

    ERIC Educational Resources Information Center

    Tally-Foos, Kay

    2005-01-01

    At the authors' school, as in many places, she struggles with making science a meaningful part of her students' lives. The teachers are working under state mandates to prepare students for reading and mathematics tests in third, fourth, and fifth grades. Often, this relegates science and social studies to a distant back burner. In an effort to

  2. Advanced Science.

    ERIC Educational Resources Information Center

    Coles, Mike; Nelms, Rick

    1996-01-01

    Describes a study that explores the depth and breadth of scientific facts, principles, and procedures which are required in the Advanced General National Vocational Qualifications (GNVQ) science through comparison with GCE Advanced level. The final report takes account of the updated 1996 version of GNVQ science. (DDR)

  3. Personalizing Science

    ERIC Educational Resources Information Center

    Danielowich, Robert M.

    2014-01-01

    Science teachers are aware of many social issues that intersect with science. These socio-scientific issues (SSIs) are "open-ended problems without clear-cut solutions [that] can be informed by scientific principles, theories, and data, butcannot be fully determined by [them]" (Sadler 2011, p. 4). This article describes the SSI lessons

  4. Shrinking Science.

    ERIC Educational Resources Information Center

    Goates, Wayne

    2002-01-01

    Describes an activity based on shrinkable thermoplastics in which students explore the percentage of shrinkage of a plastic ruler when it is heated. Includes science content knowledge behind the shrink, national science education standards related to this activity, and a complete guide. (KHR)

  5. Life sciences

    SciTech Connect

    Day, L.

    1991-04-01

    This document is the 1989--1990 Annual Report for the Life Sciences Divisions of the University of California/Lawrence Berkeley Laboratory. Specific progress reports are included for the Cell and Molecular Biology Division, the Research Medicine and Radiation Biophysics Division (including the Advanced Light Source Life Sciences Center), and the Chemical Biodynamics Division. 450 refs., 46 figs. (MHB)

  6. Soundsational Science

    ERIC Educational Resources Information Center

    Carrier, Sarah J.; Scott, Catherine Marie; Hall, Debra T.

    2012-01-01

    The science of sound helps students learn that sound is energy traveling in waves as vibrations transfer the energy through various media: solids, liquids, and gases. In addition to learning about the physical science of sound, students can learn about the sounds of different animal species: how sounds contribute to animals' survival, and how

  7. Talking Science

    ERIC Educational Resources Information Center

    Shwartz, Yael; Weizman, Ayelet; Fortus, David; Sutherland, LeeAnn; Merrit, Joi; Krajcik, Joe

    2009-01-01

    Science is a social process--one that involves particular ways of talking, reasoning, observing, analyzing, and writing, which often have meaning only when shared within the scientific community. Discussions are one of the best ways to help students learn to "talk science" and construct understanding in a social context. Since inquiry is an…

  8. Science Notes.

    ERIC Educational Resources Information Center

    Murray, A. J. S.; And Others

    1988-01-01

    Presents 31 science activities for use with high school or college science classes. Topics included are: chromatography, ecology, invertebrates, enzymes, genetics, botany, creep, crystals, diffusion, computer interfaces, acid rain, teaching techniques, chemical reactions, waves, electric fields, rainbows, electricity, magnetic fields, and a Pitot

  9. Why Science?

    ERIC Educational Resources Information Center

    Primary Science Review, 2006

    2006-01-01

    This article presents people from many walks of life, including some well-known names, who share their views about science. Adam Hart-Davis, who studied chemistry at university and is now an author, photographer, historian and broadcaster, explains why science cannot start too soon. Lis Nairn, Manager, Stratigraphy, with Fugro Robertson Ltd (Oil…

  10. Deconstructing Science

    ERIC Educational Resources Information Center

    Trifonas, Peter Pericles

    2012-01-01

    In this paper I expand on the premises of Jesse Bazzul's thesis in his paper, "Neoliberal ideology, global capitalism, and science education: engaging the question of subjectivity," exploring the implications of the ideologies within the culturally emerging logic of science exposes the incommensurability of intents and purposes in its methods and

  11. Evaluation of the Long-Term Impact of a University High School Summer Science Program on Students' Interest and Perceived Abilities in Science

    ERIC Educational Resources Information Center

    Markowitz, Dina G.

    2004-01-01

    Many biomedical research universities have established outreach programs for precollege students and teachers and partnerships with local school districts to help meet the challenges of science education reform. Science outreach programs held in university research facilities can make science more exciting and innovative for high school students

  12. Some Aspects of the Current Revolution in the Earth Sciences

    ERIC Educational Resources Information Center

    Wilson, J. Tuzo

    1969-01-01

    Summarizes the present state of sea-floor spreading theory, elaborates upon some apparent consequences,and makes some suggestions about future education in the earth sciences. The author concludes that the future of the earth sciences looks bright and exciting. (RR)

  13. Science Shorts: More than One Way to Investigate

    ERIC Educational Resources Information Center

    Coskie, Tracy L.; Davis, Kimberly J.

    2007-01-01

    An exciting element of science fairs is that they give students the opportunity to explore various interests through scientific investigation. Many students, however, mistakenly think that all investigations are experiments. This lesson can help broaden students' conceptions of science. (Contains 1 resource.)

  14. Toolkit: Becoming a Science, Technology, Engineering, and Math (STEM) Mentor

    ERIC Educational Resources Information Center

    Corporation for National and Community Service, 2010

    2010-01-01

    President Obama has recognized the need to move students from the middle to the top of the pack in math and science as a national priority. Mentorship is often cited as a key strategy for exciting, supporting, and keeping students and young scientists and engineers in the fields of science, technology, engineering, and math (STEM). This is

  15. Computer Animations a Science Teaching Aid: Contemplating an Effective Methodology

    ERIC Educational Resources Information Center

    Tannu, Kirti

    2008-01-01

    To improve quality of science education, the author suggests use of entertaining and exciting technique of animation for better understanding of scientific principles. Latest technologies are being used with more vigour to spread venomous superstitions. Better understanding of science may help students to better their scientific temper. Keeping…

  16. Attracting More Women and Minorities to the Sciences.

    ERIC Educational Resources Information Center

    Link, Claudia

    1998-01-01

    Introduces the Chautauqua short course, held to devise strategies for professors, scientists, and other members of the science community to draw and retain women and minorities in science. Concludes that everyone has a role to play in sharing the interest, excitement, and joy of scientific discovery with women and minorities. (ASK)

  17. Results from the Independent Evaluation of the Seminars on Science

    ERIC Educational Resources Information Center

    Stokes, Laura; St. John, Mark; Hirabayashi, Judy; Smith, Anita

    2007-01-01

    In 1998, the American Museum of Natural History (AMNH) launched an ambitious effort to create on-line science courses for K-12 educators that would immerse them in exciting science topics and give them access to the Museum's scientific resources (scientists, research, expeditions, collections, and exhibitions). This project, called Seminars on…

  18. "Celebrate Science" Has Formula for Hands-On Learning

    ERIC Educational Resources Information Center

    Brydolf, Carol

    2012-01-01

    Cost-effective, easily replicated program is a win-win situation for high schoolers who teach science and for their elementary students. The thank-you letter from Leslie, a grade-schooler in San Diego County's Ramona Unified School District, speaks volumes about the excitement generated by "Celebrate Science"--an innovative, standards-based

  19. Results from the Independent Evaluation of the Seminars on Science

    ERIC Educational Resources Information Center

    Stokes, Laura; St. John, Mark; Hirabayashi, Judy; Smith, Anita

    2007-01-01

    In 1998, the American Museum of Natural History (AMNH) launched an ambitious effort to create on-line science courses for K-12 educators that would immerse them in exciting science topics and give them access to the Museum's scientific resources (scientists, research, expeditions, collections, and exhibitions). This project, called Seminars on

  20. Adventures in Rocket Science. EG-2007-12-179-MSFC

    ERIC Educational Resources Information Center

    Huegele, Vince; Hill, Kristy; Terry, Brenda

    2008-01-01

    This guide was prepared as a tool useful for informal education venues (4-H, Boys and Girls Clubs, Boy Scouts, Girl Scouts, etc.), science clubs and related programs, and can be adopted for formal education settings. An exciting and productive study in rocket science can be implemented using the selected activities for the above-mentioned…

  1. Nuclear excitations and reaction mechanisms

    SciTech Connect

    Fallieros, S.; Levin, F.S.

    1990-08-01

    The main theme of this report is the study and interpretation of the sequence of events that occur during the collisions of nuclear particles. Some of the processes discussed in parts A and B involve short range interactions; others involve interactions of long range. In most of part A one of the particles in the initial or in the final state (or in both) is a photon, which serves as a probe of the second particle, which may be a nucleus, a proton, a pion or any other hadron. The complexity of the processes taking place during the collisions makes it necessary to simplify some aspects of the physical problem. This leads to the introduction of modals which are used to describe a limited number of features in as much detail as possible. The main interest is the understanding of the hadronic excitations which result from the absorption of a photon and the determination of the fundamental structure constants of the target particle. In part B, all the particles are hadrons. The purpose here is to develop and apply optimal quantal methods appropriate for describing the interacting systems. Of particular interest are three-particle collision systems in which the final state consists of three free particles. Part B also considers the process of nuclear fusion as catalyzed by bound muons.

  2. NASA/MSFC/NSSTC Science Communication Roundtable

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi L.; Gallagher, D. L.; Koczor, R. J.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    For the last several years the Science Directorate at Marshall Space Flight Center has carried out a diverse program of Internet-based science communication. The Directorate's Science Roundtable includes active researchers, NASA public relations, educators, and administrators. The Science@NASA award-winning family of Web sites features science, mathematics, and space news. The program includes extended stories about NASA science, a curriculum resource for teachers tied to national education standards, on-line activities for students, and webcasts of real-time events. Science stories cover a variety of space-related subjects and are expressed in simple terms everyone can understand. The sites address such questions as: what is space weather, what's in the heart of a hurricane, can humans live on Mars, and what is it like to live aboard the International Space Station? Along with a new look, the new format now offers articles organized by subject matter, such as astronomy, living in space, earth science or biology. The focus of sharing real-time science related events has been to involve and excite students and the public about science. Events have involved meteor showers, solar eclipses, natural very low frequency radio emissions, and amateur balloon flights. In some cases broadcasts accommodate active feedback and questions from Internet participants. Information will be provided about each member of the Science@NASA web sites.

  3. Excitation of helium ion by positron impact

    SciTech Connect

    Khan, P.; Ghosh, A.S.

    1986-01-01

    Three (1s,2s,2p) and five (1s,2s,2p,3s-bar,3p-bar) -state close-coupling methods have been employed to calculate the n = 2 excitation cross sections of helium ion by positron impact. The effect of pseudostate is found to be very pronounced in the case of 1s-2s excitation.

  4. Study of excited nucleons and their structure

    SciTech Connect

    Burkert, Volker D.

    2014-01-01

    Recent advances in the study of excited nucleons are discussed. Much of the progress has been achieved due to the availability of high precision meson production data in the photoproduction and electroproduction sectors, the development of multi-channel partial wave analysis techniques, and advances in Lattice QCD with predictions of the full excitation spectrum.

  5. What Gets a Cell Excited? Kinky Curves

    ERIC Educational Resources Information Center

    Kay, Alan R.

    2014-01-01

    Hodgkin and Huxley's (5) revealing the origins of cellular excitability is one of the great triumphs of physiology. In an extraordinarily deft series of papers, they were able to measure the essential electrical characteristics of neurons and synthesize them into a quantitative model that accounts for the excitability of neurons and other…

  6. What Gets a Cell Excited? Kinky Curves

    ERIC Educational Resources Information Center

    Kay, Alan R.

    2014-01-01

    Hodgkin and Huxley's (5) revealing the origins of cellular excitability is one of the great triumphs of physiology. In an extraordinarily deft series of papers, they were able to measure the essential electrical characteristics of neurons and synthesize them into a quantitative model that accounts for the excitability of neurons and other

  7. Vibrationally excited molecular hydrogen near Herschel 36

    SciTech Connect

    Rachford, Brian L.; Snow, Theodore P.; Ross, Teresa L.

    2014-05-10

    We present the first high resolution UV spectra toward Herschel 36, a Trapezium-like system of high-mass stars contained within the Lagoon Nebula (M8, NGC 6523). The spectra reveal extreme rovibrational excitation of molecular hydrogen in material at a single velocity or very small range of velocities, with this component presumably lying near the star system and undergoing fluorescent excitation. The overall H{sub 2} excitation is similar to, but apparently larger than, that seen toward HD 37903 which previously showed the largest vibrationally excited H{sub 2} column densities seen in UV absorption spectra. While the velocities of the highly excited H{sub 2} lines are consistent within each observation, it appears that they underwent a ∼60 km s{sup –1} redshift during the 3.6 yr between observations. In neither case does the velocity of the highly excited material match the velocity of the bulk of the line-of-sight material which appears to mostly be in the foreground of M8. Recent work shows unusually excited CH and CH{sup +} lines and several unusually broad diffuse interstellar bands toward Herschel 36. Along with the H{sub 2} excitation, all of these findings appear to be related to the extreme environment within ∼0.1 pc of the massive young stellar system.

  8. Excitation-scanning hyperspectral imaging microscope

    PubMed Central

    Favreau, Peter F.; Hernandez, Clarissa; Heaster, Tiffany; Alvarez, Diego F.; Rich, Thomas C.; Prabhat, Prashant; Leavesley, Silas J.

    2014-01-01

    Abstract. Hyperspectral imaging is a versatile tool that has recently been applied to a variety of biomedical applications, notably live-cell and whole-tissue signaling. Traditional hyperspectral imaging approaches filter the fluorescence emission over a broad wavelength range while exciting at a single band. However, these emission-scanning approaches have shown reduced sensitivity due to light attenuation from spectral filtering. Consequently, emission scanning has limited applicability for time-sensitive studies and photosensitive applications. In this work, we have developed an excitation-scanning hyperspectral imaging microscope that overcomes these limitations by providing high transmission with short acquisition times. This is achieved by filtering the fluorescence excitation rather than the emission. We tested the efficacy of the excitation-scanning microscope in a side-by-side comparison with emission scanning for detection of green fluorescent protein (GFP)-expressing endothelial cells in highly autofluorescent lung tissue. Excitation scanning provided higher signal-to-noise characteristics, as well as shorter acquisition times (300  ms/wavelength band with excitation scanning versus 3  s/wavelength band with emission scanning). Excitation scanning also provided higher delineation of nuclear and cell borders, and increased identification of GFP regions in highly autofluorescent tissue. These results demonstrate excitation scanning has utility in a wide range of time-dependent and photosensitive applications. PMID:24727909

  9. Excitation-scanning hyperspectral imaging microscope.

    PubMed

    Favreau, Peter F; Hernandez, Clarissa; Heaster, Tiffany; Alvarez, Diego F; Rich, Thomas C; Prabhat, Prashant; Leavesley, Silas J

    2014-04-01

    Hyperspectral imaging is a versatile tool that has recently been applied to a variety of biomedical applications, notably live-cell and whole-tissue signaling. Traditional hyperspectral imaging approaches filter the fluorescence emission over a broad wavelength range while exciting at a single band. However, these emission-scanning approaches have shown reduced sensitivity due to light attenuation from spectral filtering. Consequently, emission scanning has limited applicability for time-sensitive studies and photosensitive applications. In this work, we have developed an excitation-scanning hyperspectral imaging microscope that overcomes these limitations by providing high transmission with short acquisition times. This is achieved by filtering the fluorescence excitation rather than the emission. We tested the efficacy of the excitation-scanning microscope in a side-by-side comparison with emission scanning for detection of green fluorescent protein (GFP)-expressing endothelial cells in highly autofluorescent lung tissue. Excitation scanning provided higher signal-to-noise characteristics, as well as shorter acquisition times (300  ms/wavelength band with excitation scanning versus 3  s/wavelength band with emission scanning). Excitation scanning also provided higher delineation of nuclear and cell borders, and increased identification of GFP regions in highly autofluorescent tissue. These results demonstrate excitation scanning has utility in a wide range of time-dependent and photosensitive applications. PMID:24727909

  10. 46 CFR 111.12-3 - Excitation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL... (incorporated by reference; see 46 CFR 110.10-1), except that those for mobile offshore drilling units must meet... 46 CFR 110.10-1). In particular, no static exciter may be used for excitation of an...

  11. 46 CFR 111.12-3 - Excitation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL... (incorporated by reference; see 46 CFR 110.10-1), except that those for mobile offshore drilling units must meet... 46 CFR 110.10-1). In particular, no static exciter may be used for excitation of an...

  12. 46 CFR 111.12-3 - Excitation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL... (incorporated by reference; see 46 CFR 110.10-1), except that those for mobile offshore drilling units must meet... 46 CFR 110.10-1). In particular, no static exciter may be used for excitation of an...

  13. Ensemble density functional theory method correctly describes bond dissociation, excited state electron transfer, and double excitations

    NASA Astrophysics Data System (ADS)

    Filatov, Michael; Huix-Rotllant, Miquel; Burghardt, Irene

    2015-05-01

    State-averaged (SA) variants of the spin-restricted ensemble-referenced Kohn-Sham (REKS) method, SA-REKS and state-interaction (SI)-SA-REKS, implement ensemble density functional theory for variationally obtaining excitation energies of molecular systems. In this work, the currently existing version of the SA-REKS method, which included only one excited state into the ensemble averaging, is extended by adding more excited states to the averaged energy functional. A general strategy for extension of the REKS-type methods to larger ensembles of ground and excited states is outlined and implemented in extended versions of the SA-REKS and SI-SA-REKS methods. The newly developed methods are tested in the calculation of several excited states of ground-state multi-reference systems, such as dissociating hydrogen molecule, and excited states of donor-acceptor molecular systems. For hydrogen molecule, the new method correctly reproduces the distance dependence of the lowest excited state energies and describes an avoided crossing between the doubly excited and singly excited states. For bithiophene-perylenediimide stacked complex, the SI-SA-REKS method correctly describes crossing between the locally excited state and the charge transfer excited state and yields vertical excitation energies in good agreement with the ab initio wavefunction methods.

  14. Ensemble density functional theory method correctly describes bond dissociation, excited state electron transfer, and double excitations

    SciTech Connect

    Filatov, Michael; Huix-Rotllant, Miquel; Burghardt, Irene

    2015-05-14

    State-averaged (SA) variants of the spin-restricted ensemble-referenced Kohn-Sham (REKS) method, SA-REKS and state-interaction (SI)-SA-REKS, implement ensemble density functional theory for variationally obtaining excitation energies of molecular systems. In this work, the currently existing version of the SA-REKS method, which included only one excited state into the ensemble averaging, is extended by adding more excited states to the averaged energy functional. A general strategy for extension of the REKS-type methods to larger ensembles of ground and excited states is outlined and implemented in extended versions of the SA-REKS and SI-SA-REKS methods. The newly developed methods are tested in the calculation of several excited states of ground-state multi-reference systems, such as dissociating hydrogen molecule, and excited states of donor–acceptor molecular systems. For hydrogen molecule, the new method correctly reproduces the distance dependence of the lowest excited state energies and describes an avoided crossing between the doubly excited and singly excited states. For bithiophene–perylenediimide stacked complex, the SI-SA-REKS method correctly describes crossing between the locally excited state and the charge transfer excited state and yields vertical excitation energies in good agreement with the ab initio wavefunction methods.

  15. Ensemble density functional theory method correctly describes bond dissociation, excited state electron transfer, and double excitations.

    PubMed

    Filatov, Michael; Huix-Rotllant, Miquel; Burghardt, Irene

    2015-05-14

    State-averaged (SA) variants of the spin-restricted ensemble-referenced Kohn-Sham (REKS) method, SA-REKS and state-interaction (SI)-SA-REKS, implement ensemble density functional theory for variationally obtaining excitation energies of molecular systems. In this work, the currently existing version of the SA-REKS method, which included only one excited state into the ensemble averaging, is extended by adding more excited states to the averaged energy functional. A general strategy for extension of the REKS-type methods to larger ensembles of ground and excited states is outlined and implemented in extended versions of the SA-REKS and SI-SA-REKS methods. The newly developed methods are tested in the calculation of several excited states of ground-state multi-reference systems, such as dissociating hydrogen molecule, and excited states of donor-acceptor molecular systems. For hydrogen molecule, the new method correctly reproduces the distance dependence of the lowest excited state energies and describes an avoided crossing between the doubly excited and singly excited states. For bithiophene-perylenediimide stacked complex, the SI-SA-REKS method correctly describes crossing between the locally excited state and the charge transfer excited state and yields vertical excitation energies in good agreement with the ab initio wavefunction methods. PMID:25978880

  16. Science Instructors' Views of Science and Nature of Science

    ERIC Educational Resources Information Center

    Karakas, Mehmet

    2011-01-01

    This qualitative study examined how college science faculty who teach introductory level undergraduate science courses including the fields of chemistry, biology, physics, and earth science, understand and define science and nature of science (NOS). Participants were seventeen science instructors from five different institutions in the…

  17. Science Policy: Pangs of Science

    ERIC Educational Resources Information Center

    Handler, Philip

    1978-01-01

    Presented is the prepared text of a public lecture given by the president of the National Academy of Sciences. Dr. Handler attempts to articulate the state of science today. He deals with such issues as nuclear power and genetic engineering. (MDR)

  18. Science Indicators and Science Priorities.

    ERIC Educational Resources Information Center

    Brooks, Harvey

    1982-01-01

    Discusses science/society interface and difficulties involved in developing realistic science indicators. Topics include: intrinsic vs. extrinsic indicators; four problems society faces as a result of technological activities (toxic chemicals, radioactive wastes, auto safety, cancer); research and development (R&D) priorities; international

  19. Teaching Science. Ripping into Science.

    ERIC Educational Resources Information Center

    Leyden, Michael B.

    1995-01-01

    Describes how one activity can lead students to investigate and understand science concepts. Example provided involves ripping of a newspaper and the resultant discussions on saws, fabric, meat, and newsprint. Suggests that this activity can be a bridge to study in language arts, career education, graphic arts, mathematics, science, and

  20. Science Indicators and Science Priorities.

    ERIC Educational Resources Information Center

    Brooks, Harvey

    1982-01-01

    Discusses science/society interface and difficulties involved in developing realistic science indicators. Topics include: intrinsic vs. extrinsic indicators; four problems society faces as a result of technological activities (toxic chemicals, radioactive wastes, auto safety, cancer); research and development (R&D) priorities; international…

  1. Lessons Learned from Conducting a K-12 Project to Revitalize Achievement by Using Instrumentation in Science Education

    ERIC Educational Resources Information Center

    Kapila, Vikram; Iskander, Magued

    2014-01-01

    A student's first introduction to engineering and technology is typically through high school science labs. Unfortunately, in many high schools, science labs often make use of antiquated tools that fail to deliver exciting lab content. As a result, many students are turned off by science, fail to excel on standardized science exams, and do

  2. Lessons Learned from Conducting a K-12 Project to Revitalize Achievement by Using Instrumentation in Science Education

    ERIC Educational Resources Information Center

    Kapila, Vikram; Iskander, Magued

    2014-01-01

    A student's first introduction to engineering and technology is typically through high school science labs. Unfortunately, in many high schools, science labs often make use of antiquated tools that fail to deliver exciting lab content. As a result, many students are turned off by science, fail to excel on standardized science exams, and do…

  3. Revolutionary Science.

    PubMed

    Casadevall, Arturo; Fang, Ferric C

    2016-01-01

    On rare occasions in the history of science, remarkable discoveries transform human society and forever alter mankind's view of the world. Examples of such discoveries include the heliocentric theory, Newtonian physics, the germ theory of disease, quantum theory, plate tectonics and the discovery that DNA carries genetic information. The science philosopher Thomas Kuhn famously described science as long periods of normality punctuated by times of crisis, when anomalous observations culminate in revolutionary changes that replace one paradigm with another. This essay examines several transformative discoveries in the light of Kuhn's formulation. We find that each scientific revolution is unique, with disparate origins that may include puzzle solving, serendipity, inspiration, or a convergence of disparate observations. The causes of revolutionary science are varied and lack an obvious common structure. Moreover, it can be difficult to draw a clear distinction between so-called normal and revolutionary science. Revolutionary discoveries often emerge from basic science and are critically dependent on nonrevolutionary research. Revolutionary discoveries may be conceptual or technological in nature, lead to the creation of new fields, and have a lasting impact on many fields in addition to the field from which they emerge. In contrast to political revolutions, scientific revolutions do not necessarily require the destruction of the previous order. For humanity to continue to benefit from revolutionary discoveries, a broad palette of scientific inquiry with a particular emphasis on basic science should be supported. PMID:26933052

  4. Science packages

    NASA Astrophysics Data System (ADS)

    1997-01-01

    Primary science teachers in Scotland have a new updating method at their disposal with the launch of a package of CDi (Compact Discs Interactive) materials developed by the BBC and the Scottish Office. These were a response to the claim that many primary teachers felt they had been inadequately trained in science and lacked the confidence to teach it properly. Consequently they felt the need for more in-service training to equip them with the personal understanding required. The pack contains five disks and a printed user's guide divided up as follows: disk 1 Investigations; disk 2 Developing understanding; disks 3,4,5 Primary Science staff development videos. It was produced by the Scottish Interactive Technology Centre (Moray House Institute) and is available from BBC Education at £149.99 including VAT. Free Internet distribution of science education materials has also begun as part of the Global Schoolhouse (GSH) scheme. The US National Science Teachers' Association (NSTA) and Microsoft Corporation are making available field-tested comprehensive curriculum material including 'Micro-units' on more than 80 topics in biology, chemistry, earth and space science and physics. The latter are the work of the Scope, Sequence and Coordination of High School Science project, which can be found at http://www.gsh.org/NSTA_SSandC/. More information on NSTA can be obtained from its Web site at http://www.nsta.org.

  5. Shenandoah elementary science enrichment program

    SciTech Connect

    Garrett, P.

    1994-12-31

    Shenandoah Elementary School is a rural educational facility located in the farmlands of Indiana. The Elementary Science Enrichment Program was established to create a learning atmosphere that encourages scientific thinking and problem-solving. Its inception was founded on the belief that the concepts and process skills inherent in the teaching of science are critical to the early intellectual development of elementary students. The program was established through speaking engagements at the local and state level which resulted in the necessary support to insure its continuation. All students in grades K-5 meet for weekly science activities in our elementary lab to investigate many exciting curricular areas including planaria regeneration, star life cycles, and acid rain telecommunications. This allows for in-depth exploration of the science process skills which culminate in a variety of products including student portfolios, hands-on assessments, simulations and global data communications. These activities are extended through family science and the modeling of science instructional techniques for classroom educators.

  6. Effects of core turbulence on jet excitability

    NASA Technical Reports Server (NTRS)

    Mankbadi, Reda R.; Raman, Ganesh; Rice, Edward J.

    1989-01-01

    The effects of varying freestream core turbulence on the evolution of a circular jet with and without tonal excitation are examined. Measurements are made on an 8.8 cm diameter jet at a Mach number of 0.3. The jet is excitated by plane waves at Strouhal number 0.5. For the excited and unexcited cases the turbulence level is varied by screens and grids placed upstream of the nozzle exit. The experiment results are compared with a theoretical model which incorporates a variable core turbulence and considers the energy interactions between the mean flow, the turbulence and the forced component. Both data and theory indicate that increasing the freestream turbulence diminishes the excitability of the jet and reduces the effect of excitation on the spreading rate of the jet.

  7. Effects of core turbulence on jet excitability

    NASA Technical Reports Server (NTRS)

    Mankbadi, Reda R.; Rice, Edward J.; Raman, Ganesh

    1989-01-01

    The effects of varying freestream core turbulence on the evolution of a circular jet with and without tonal excitation are examined. Measurements are made on an 8.8 cm diameter jet at a Mach number of 0.3. The jet is excited by plane waves at Strouhal number 0.5. For the excited and unexcited cases the turbulence level is varied by screens and grids placed upstream of the nozzle exit. The experiment results are compared with a theoretical model which incorporates a variable core turbulence and considers the energy interactions between the mean flow, the turbulence and the forced component. Both data and theory indicate that increasing the freestream turbulence diminishes the excitability of the jet and reduces the effect of excitation on the spreading rate of the jet.

  8. Numerical simulation of excited jet mixing layers

    NASA Technical Reports Server (NTRS)

    Scott, J. N.; Hankey, W. L.

    1987-01-01

    A numerical simulation of unsteady flow in jet mixing layers, both with and without external excitation, has been performed by solving the time-dependent compressible Navier-Stokes equations. Computations were performed on a CRAY X-MP computer using MacCormick's explicit finite difference algorithm. Different excitation methods were investigated and were shown to be very effective in controlling the well organized periodic production, shedding and pairing of large scale vortex structures. It is found that pressure excitation was generally more effective than temperature excitation, and that grid refinement results in substantial improvement in the resolution of unsteady features. The location and orientation, in addition to the frequency, of the excitation source are shown to have a significant influence on the production and interaction of large scale vortex structures in the jet mixing layer.

  9. Information operations with an excitable field.

    PubMed

    Motoike, I; Yoshikawa, K

    1999-05-01

    It is well established that a traveling wave can be generated on an excitable field, which is described with a pair of partial differential equations for an activator and inhibitor. In the present paper, we use a numerical simulation to show that the traveling wave, or signaling pulse, can be transmitted from an excitable field to an opposing excitable field via an intervening passive diffusion field in a characteristic manner depending on the spatial geometry of the excitable fields. Using such characteristics, it is possible to design various kinds of logic gates together with a time-sequential memory device. Thus, these functions can perform time-sensitive operations in the absence of any controlling clock. It may be possible to accomplish these computations with excitable fields in an actual system, or to create a "field computer" composed of electronic active and passive units. PMID:11969495

  10. Impact of ground- and excited-state aromaticity on cyclopentadiene and silole excitation energies and excited-state polarities.

    PubMed

    Jorner, Kjell; Emanuelsson, Rikard; Dahlstrand, Christian; Tong, Hui; Denisova, Aleksandra V; Ottosson, Henrik

    2014-07-21

    A new qualitative model for estimating the properties of substituted cyclopentadienes and siloles in their lowest ??* excited states is introduced and confirmed through quantum chemical calculations, and then applied to explain earlier reported experimental excitation energies. According to our model, which is based on excited-state aromaticity and antiaromaticity, siloles and cyclopentadienes are cross-hyperconjugated "aromatic chameleons" that adapt their electronic structures to conform to the various aromaticity rules in different electronic states (Hckel's rule in the ?(2) electronic ground state (S0) and Baird's rule in the lowest ??* excited singlet and triplet states (S1 and T1)). By using pen-and-paper arguments, one can explain polarity changes upon excitation of substituted cyclopentadienes and siloles, and one can tune their lowest excitation energies by combined considerations of ground- and excited-state aromaticity/antiaromaticity effects. Finally, the "aromatic chameleon" model can be extended to other monocyclic compound classes of potential use in organic electronics, thereby providing a unified view of the S0, T1, and S1 states of a range of different cyclic cross-?-conjugated and cross-hyperconjugated compound classes. PMID:25043523

  11. Tracking the charge and spin dynamics of electronic excited states in inorganic complexes

    NASA Astrophysics Data System (ADS)

    Gaffney, Kelly

    2015-03-01

    Inorganic complexes have many advantageous properties for solar energy applications, including strong visible absorption and photocatalytic activity. Whether used as a photocatalyst or a photosensitizer, the lifetime of electronic excited states and the earth abundance of the molecular components represent a key property for solar energy applications. These dual needs have undermined the usefulness of many coordination compounds. Isoelectronic iron and ruthenium based complexes represent a clear example. Ru-polypyridal based molecules have been the workhorse of solar energy related research and dye sensitized solar cells for decades, but the replacement of low abundance Ru with Fe leads to million-fold reductions in metal to ligand charge transfer (MLCT) excited state lifetimes. Understanding the origin of this million-fold reduction in lifetime and how to control excited state relaxation in 3d-metal complexes motivates the work I will discuss. We have used the spin sensitivity of hard x-ray fluorescence spectroscopy and the intense femtosecond duration pulses generated by the LCLS x-ray laser to probe the spin dynamics in a series of electronically excited [Fe(CN)6-2N(2,2'-bipyridine)N]2 N - 4 complexes, with N = 1-3. These femtosecond resolution measurements demonstrate that modification of the solvent and ligand environment can lengthen the MLCT excited state lifetime by more than two orders of magnitude. They also verify the role of triplet ligand field excited states in the spin crossover dynamics from singlet to quintet spin configurations. Work supported by the AMOS program within the Chemical Sciences, Geosciences, and Biosciences Division of the Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

  12. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1987

    1987-01-01

    This section of the journal includes several short notes on science activities and materials for secondary schools. Activities and materials are included that relate to biology, microbiology, microcomputers, chemistry, and physics. (RH)

  13. Science Facilities.

    ERIC Educational Resources Information Center

    Biehle, James T.

    2002-01-01

    Describes how schools in Carroll County, Maryland; Toronto, Ontario; Durham, North Carolina; Englewood, Colorado; and Troy, New York, are renovating their vocational areas for inquiry-based, hands-on science learning. Includes sample floor plans and photographs. (EV)

  14. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1989

    1989-01-01

    Twenty-two activities are presented. Topics include: acid rain, microcomputers, fish farming, school-industry research projects, enzymes, equilibrium, assessment, science equipment, logic, Archimedes principle, electronics, optics, and statistics. (CW)

  15. Science Notes.

    ERIC Educational Resources Information Center

    Thurman, Shirley; And Others

    1988-01-01

    Describes 36 science activities. Topics include: osmosis, fermentation, anhydrobiotic organisms, breathing monitors, trypsin, weeds, amyloplasts, electrolysis, polarimeters, ethene ripening of fruit, colorimetry, diffusion, redox reactions, equilibria, acid-base relationships, electricity, power, resonance, measurement, parallax, amplifiers,…

  16. Scuba Science.

    ERIC Educational Resources Information Center

    Glickstein, Neil

    2000-01-01

    Introduces an integrated unit on scuba science. Studies oxygen in kinetic theory, Boyle's law, Charles's law, Dalton's law, human circulatory and respiratory systems, and diving dangers such as decompression sickness. (YDS)

  17. Forensic Science

    ERIC Educational Resources Information Center

    Cobb, P. G. W.

    1973-01-01

    Summarizes the type of work carried out by forensic chemists and the minimum qualification needed for appointment. Indicates that there are eight Home Office regional forensic science laboratories in addition to the Central Research Establishment at Aldermaston. (CC)

  18. Forensic Science.

    ERIC Educational Resources Information Center

    Brettell, T. A.; Saferstein, R.

    1989-01-01

    Presents a review of articles appealing to forensic practitioners. Topics include: drugs and poisons, forensic biochemistry, and trace evidence. Lists noteworthy books published on forensic science topics since 1986. (MVL)

  19. Communicating Science

    USGS Publications Warehouse

    Farris, Gaye S.

    2005-01-01

    For science to have an impact, it must be communicated and easily accessible. The USGS National Wetlands Research Center communicates its research findings through several ways: publishing, the Web, the library, and education and outreach.

  20. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1990

    1990-01-01

    Included are 30 science activities that include computer monitoring, fieldwork, enzyme activity, pH, drugs, calorimeters, Raoult's Law, food content, solubility, electrochemistry, titration, physical properties of materials, gel filtration, energy, concepts in physics, and electricity. (KR)

  1. Dismal Science

    PubMed Central

    Evans, Robert G.

    2009-01-01

    “No prediction, no science.” By this standard, the past year has not been kind to the pretensions of “economic science,” Nobel prizes notwithstanding. The issue is more than semantic. As Neil Postman (1992) pointed out, sciences study natural processes that repeat themselves under constant conditions. The social disciplines study practices of human communities that are embedded in history. There are no constant conditions; it is impossible to step into the same river twice (Heraclitus). “Physics envy” has led mainstream economic theorists to attempt to understand their discipline through methods and models borrowed from the natural sciences. (By unfortunate coincidence, these have reinforced a certain class of ideological preconceptions and associated economic interests.) Today the results of this methodological mismatch speak for themselves. PMID:20436803

  2. Science Notes.

    ERIC Educational Resources Information Center

    Thurman, Shirley; And Others

    1988-01-01

    Describes 36 science activities. Topics include: osmosis, fermentation, anhydrobiotic organisms, breathing monitors, trypsin, weeds, amyloplasts, electrolysis, polarimeters, ethene ripening of fruit, colorimetry, diffusion, redox reactions, equilibria, acid-base relationships, electricity, power, resonance, measurement, parallax, amplifiers,

  3. Science Weekly.

    ERIC Educational Resources Information Center

    Science and Children, 1986

    1986-01-01

    Reviews the space classroom that would have been conducted by Christa McAuliffe during the space shuttle flight. Includes lab activities, word puzzles, vocabulary lists, and graph reading exercises for elementary science students. (ML)

  4. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1990

    1990-01-01

    Presented are 25 science activities on colorations of prey, evolution, blood, physiology, nutrition, enzyme kinetics, leaf pigments, analytical chemistry, milk, proteins, fermentation, surface effects of liquids, magnetism, drug synthesis, solvents, wintergreen synthesis, chemical reactions, multicore cables, diffraction, air resistance,

  5. Overnight Science.

    ERIC Educational Resources Information Center

    Smith, Nancy N.; Stahl, Robert J.

    1981-01-01

    Outlines objectives for an elementary science camping program and summarizes general operational procedures. Campsite activities related to such topics as microorganisms, eye and sight, nature trails, bees, carpentry, and astronomy are described. (DS)

  6. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1985

    1985-01-01

    Presents 23 experiments, activities, field projects and computer programs in the biological and physical sciences. Instructional procedures, experimental designs, materials, and background information are suggested. Topics include fluid mechanics, electricity, crystals, arthropods, limpets, acid neutralization, and software evaluation. (ML)

  7. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1987

    1987-01-01

    Describes 20 teaching activities and experiments appropriate for use with various secondary school science classes. Instructional activities include the study of catalase, raising bees, a game about equilibrium, spectrometers, lead iodide, resonance, graphing, and electromagnetic waves. (TW)

  8. Science Scenarios.

    ERIC Educational Resources Information Center

    Cronin-Jones, Linda

    2000-01-01

    Focuses on using science-related issues in classrooms. Explains how to select these issues and create a scenario, and presents a sample scenario for a role-playing activity. Provides several format structures for role-plays. (YDS)

  9. iBiology: communicating the process of science

    PubMed Central

    Goodwin, Sarah S.

    2014-01-01

    The Internet hosts an abundance of science video resources aimed at communicating scientific knowledge, including webinars, massive open online courses, and TED talks. Although these videos are efficient at disseminating information for diverse types of users, they often do not demonstrate the process of doing science, the excitement of scientific discovery, or how new scientific knowledge is developed. iBiology (www.ibiology.org), a project that creates open-access science videos about biology research and science-related topics, seeks to fill this need by producing videos by science leaders that make their ideas, stories, and experiences available to anyone with an Internet connection. PMID:25080124

  10. iBiology: communicating the process of science.

    PubMed

    Goodwin, Sarah S

    2014-08-01

    The Internet hosts an abundance of science video resources aimed at communicating scientific knowledge, including webinars, massive open online courses, and TED talks. Although these videos are efficient at disseminating information for diverse types of users, they often do not demonstrate the process of doing science, the excitement of scientific discovery, or how new scientific knowledge is developed. iBiology (www.ibiology.org), a project that creates open-access science videos about biology research and science-related topics, seeks to fill this need by producing videos by science leaders that make their ideas, stories, and experiences available to anyone with an Internet connection. PMID:25080124

  11. The National Climate Change and Wildlife Science Center and Department of the Interior Climate Science Centers annual report for 2014

    USGS Publications Warehouse

    Varela Minder, Elda; Padgett, Holly A.

    2015-01-01

    The National Climate Change and Wildlife Science Center (NCCWSC) and the Department of the Interior (DOI) Climate Science Centers (CSCs) had another exciting year in 2014. The NCCWSC moved toward focusing their science funding on several high priority areas and, along with the CSCs, gained new agency partners; contributed to various workshops, meetings, publications, student activities, and Tribal/indigenous activities; increased outreach; and more.

  12. Communicating the science of the 11-year sunspot cycle to the general public

    NASA Astrophysics Data System (ADS)

    Choudhuri, A. R.

    2015-03-01

    Astrophysics is one branch of science which excites the imagination of the general public. Pioneer science popularizers like George Gamow and Fred Hoyle wrote on different aspects of astrophysics. However, of late, we see a trend which I find disturbing. While it has become extremely fashionable to write popular science books on cosmology, other areas of astrophysics are grossly neglected.

  13. Three Steps for Better Reading in Science: Before, During, and After

    ERIC Educational Resources Information Center

    Walton, Susan

    2006-01-01

    It is exciting to have a beautiful new science textbook--if students can read it! Unfortunately, many students can not read their science textbooks unassisted. This may be because students are reading below grade level, or because the material, like that of many science texts, has a readability one or more grade levels above the grade in which it…

  14. Resonant excitation of plasma wakefield

    NASA Astrophysics Data System (ADS)

    Fang, Yun

    Particle accelerators are the main tool for discovering new elementary particles. Plasma based accelerator (PWFA) has been proven a very attractive new acceleration technique due to the large acceleration gradient it has reached (>50GV/m), which is two to three orders higher than the conventional radio frequency accelerators. PWFA is essentially an energy transformer transferring the energy from the drive bunches to witness bunches. For a future more compact and more affordable linear electron/positron collider, such an accelerator will require drive bunches with small longitudinal size (on the order of 100 um) and multi-kilojules of energy to access the new physics at the energy frontier. However, present relativistic electron bunch drivers carry less than 100Joules, thereby limiting the energy gain by the accelerated bunch to less than 100Joules. Proton bunches produced at CERN have been proven as potential drivers for PWFA due to the many tens of kilojules energy they carry (1e11 particles, 3.5-7TeV per particle). However, the CERN proton bunches are too long (approximately 12cm) to drive the wakefield efficiently. It has been proposed that a long particle bunch (protons, electrons, positrons, ... ) traveling in dense plasmas is subject to self-modulation instability (SMI), which transversely modulates a long bunch into multiple short bunches (on the scale of plasma wavelength) and therefore results in high acceleration amplitudes through resonant excitation. In this thesis, we demonstrate the first experimental evidence for the seeding of SMI with an electron bunch. We also use numerical simulations to study the SMI development with a higher-charge electron bunch and propose a possible experiment to demonstrate the transverse modulation directly in experiments. Moreover, we investigate with simulations the effect of transverse plasma radius on the SMI development, which is an important factor to consider when designing plasmas for future SMI and SMI-based experiments. Besides efficient drivers such as high-energy proton bunches, the PWFA also requires high transformer ratio (an indication of energy transfer efficiency) so that the witness bunch can gain energy efficiently from the drive bunch. In this thesis, we explore the possibility of reaching high transformer ratio in the weakly nonlinear PWFA regime so that the witness bunch particles can gain many times the energy of the drive bunch particles in a single acceleration stage.

  15. Seismic excitation by space shuttles

    USGS Publications Warehouse

    Kanamori, H.; Mori, J.; Sturtevant, B.; Anderson, D.L.; Heaton, T.

    1992-01-01

    Shock waves generated by the space shuttles Columbia (August 13, 1989), Atlantis (April 11, 1991) and Discovery (September 18, 1991) on their return to Edwards Air Force Base, California, were recorded by TERRAscope (Caltech's broadband seismic network), the Caltech-U.S.G.S Southern California Seismic Network (SCSN), and the University of Southern California (USC) Los Angeles Basin Seismic Network. The spatial pattern of the arrival times exhibits hyperbolic shock fronts from which the path, velocity and altitude of the space shuttle could be determined. The shock wave was acoustically coupled to the ground, converted to a seismic wave, and recorded clearly at the broadband TERRAscope stations. The acoustic coupling occurred very differently depending on the conditions of the Earth's surface surrounding the station. For a seismic station located on hard bedrock, the shock wave (N wave) was clearly recorded with little distortion. Aside from the N wave, very little acoustic coupling of the shock wave energy to the ground occurred at these sites. The observed N wave record was used to estimate the overpressure of the shock wave accurately; a pressure change of 0.5 to 2.2 mbars was obtained. For a seismic station located close to the ocean or soft sedimentary basins, a significant amount of shock wave energy was transferred to the ground through acoustic coupling of the shock wave and the oceanic Rayleigh wave. A distinct topography such as a mountain range was found effective to couple the shock wave energy to the ground. Shock wave energy was also coupled to the ground very effectively through large man made structures such as high rise buildings and offshore oil drilling platforms. For the space shuttle Columbia, in particular, a distinct pulse having a period of about 2 to 3 seconds was observed, 12.5 s before the shock wave, with a broadband seismograph in Pasadena. This pulse was probably excited by the high rise buildings in downtown Los Angeles which were simultaneously hit by the space shuttle shock waves. The proximity of the natural periods of the high rise buildings and the modal periods of the Los Angeles basin enabled efficient energy transfer from shock wave to seismic wave. ?? 1992 Springer-Verlag.

  16. Crossing borders: High school science teachers learning to teach the specialized language of science

    NASA Astrophysics Data System (ADS)

    Patrick, Jennifer Drake

    The highly specialized language of science is both challenging and alienating to adolescent readers. This study investigated how secondary science teachers learn to teach the specialized language of science in their classrooms. Three research questions guided this study: (a) what do science teachers know about teaching reading in science? (b) what understanding about the unique language demands of science reading do they construct through professional development? and (c) how do they integrate what they have learned about these specialized features of science language into their teaching practices? This study investigated the experience of seven secondary science teachers as they participated in a professional development program designed to teach them about the specialized language of science. Data sources included participant interviews, audio-taped professional development sessions, field notes from classroom observations, and a prior knowledge survey. Results from this study suggest that science teachers (a) were excited to learn about disciplinary reading practices, (b) developed an emergent awareness of the specialized features of science language and the various genres of science writing, and (c) recognized that the challenges of science reading goes beyond vocabulary. These teachers' efforts to understand and address the language of science in their teaching practices were undermined by their lack of basic knowledge of grammar, availability of time and resources, their prior knowledge and experiences, existing curriculum, and school structure. This study contributes to our understanding of how secondary science teachers learn about disciplinary literacy and apply that knowledge in their classroom instruction. It has important implications for literacy educators and science educators who are interested in using language and literacy practices in the service of science teaching and learning. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  17. Two-photon imaging with longer wavelength excitation in intact Arabidopsis tissues.

    PubMed

    Mizuta, Yoko; Kurihara, Daisuke; Higashiyama, Tetsuya

    2015-09-01

    In vivo imaging of living organisms is an important tool to investigate biological phenomena. Two-photon excitation microscopy (2PEM) is a laser-scanning microscopy that provides noninvasive, deep imaging in living organisms based on the principle of multiphoton excitation. However, application of 2PEM to plant tissues has not been fully developed, as plant-specific autofluorescence, optically dense tissues, and multiple light-scattering structures diminish the clarity of imaging. In this study, the advantages of 2PEM were identified for deep imaging of living and intact Arabidopsis thaliana tissues. When compared to single-photon imaging, near-infrared 2PEM, especially at 1000 nm, reduced chloroplast autofluorescence; autofluorescence also decreased in leaves, roots, pistils, and pollen grains. For clear and deep imaging, longer excitation wavelengths using the orange fluorescent proteins (FPs) TagRFP and tdTomato gave better results than with other colors. 2PEM at 980 nm also provided multicolor imaging by simultaneous excitation, and the combination of suitable FPs and excitation wavelengths allowed deep imaging of intact cells in root tips and pistils. Our results demonstrated the importance of choosing both suitable FPs and excitation wavelengths for clear two-photon imaging. Further advances in in vivo analysis using 2PEM will facilitate more extensive studies in the plant biological sciences. PMID:25588923

  18. Relativistic dynamical spin excitations of magnetic adatoms

    NASA Astrophysics Data System (ADS)

    dos Santos Dias, M.; Schweflinghaus, B.; Blügel, S.; Lounis, S.

    2015-02-01

    We present a first-principles theory of dynamical spin excitations in the presence of spin-orbit coupling. The broken global spin rotational invariance leads to a new sum rule. We explore the competition between the magnetic anisotropy energy and the external magnetic field, as well as the role of electron-hole excitations, through calculations for 3 d -metal adatoms on the Cu(111) surface. The spin excitation resonance energy and lifetime display nontrivial behavior, establishing the strong impact of relativistic effects. We legitimate the use of the Landau-Lifshitz-Gilbert equation down to the atomic limit, but with parameters that differ from a stationary theory.

  19. Electron-impact excitation of interstellar molecules

    NASA Astrophysics Data System (ADS)

    Faure, A.; Tennyson, J.; Varambhia, H. N.; Kokoouline, V.; Greene, C. H.; Stoecklin, T.

    2007-07-01

    Electron-impact excitation of molecules plays a crucial role in astrophysical environments where the electron fraction is higher than about 10-5, e.g. in the diffuse interstelar medium, in shocks and comets. We present here recent ab initio calculations of rate coefficients for the rotational excitation of HCN and HCO^+ by thermal electrons. Our calculations are based on the molecular R-matrix method combined with the Adiabatic-Nuclei-Rotation (ANR) approximation corrected for threshold effects. Our major results are i) the prediction of collisional propensity rules less rigorous than previously assumed and ii) the prediction of significant excitation differences between ionic and neutral molecules.

  20. Spatiotemporal dynamics of networks of excitable nodes

    NASA Astrophysics Data System (ADS)

    Steele, Aaron J.; Tinsley, Mark; Showalter, Kenneth

    2006-03-01

    A network of excitable nodes based on the photosensitive Belousov-Zhabotinsky reaction is studied in experiments and simulations. The addressable medium allows both local and nonlocal links between the nodes. The initial spread of excitation across the network as well as the asymptotic oscillatory behavior are described. Synchronization of the spatiotemporal dynamics occurs by entrainment to high-frequency network pacemakers formed by excitation loops. Analysis of the asymptotic behavior reveals that the dynamics of the network is governed by a subnetwork selected during the initial transient period.

  1. Excitability in a nonlinear magnetoacoustic resonator.

    PubMed

    Snchez-Morcillo, V J; Redondo, J; Martnez-Mora, J

    2007-01-01

    We report a nonlinear acoustic system displaying excitability. The considered system is a magnetostrictive material where acoustic waves are parametrically generated. For a set of parameters, the system presents homoclinic and heteroclinic dynamics, whose boundaries define an excitability domain. The excitable behavior is characterized by analyzing the response of the system to different external stimuli. Single-spiking and bursting regimes have been identified. All these neuronlike properties are here predicted to occur in magnetostrictive materials, which are the basis of many smart systems and applications. PMID:17358217

  2. Electron-impact excitation of holmium atoms

    SciTech Connect

    Smirnov, Yu M

    2000-06-30

    The electron-impact excitation of holmium atoms was studied by the method of extended crossing beams. The cross sections and the optical excitation functions were obtained for odd levels of Ho I, including the 22014 cm{sup -1} laser level. Over 99% of the atoms were shown to reside in the ground level prior to collisions with electrons. Also measured were the excitation cross sections for six even levels, which presumably participate in the formation of inversion population in a gas-discharge holmium vapour laser. (laser applications and other topics in quantum electronics)

  3. Teaching Science in the Home

    NASA Astrophysics Data System (ADS)

    Ream, J. B.

    2011-12-01

    How to effectively teach science in a classroom setting has long been a topic of discussion. Teachers are given specific guidelines on what to teach in the school curriculum and outreach programs are commonly used to help teach science in classrooms through demonstrations and other activities. However, a growing number of people are taking their children out of traditional schools and choosing instead to teach them in their own homes. Statistics show that between 1999 and 2007, the number of homeschoolers rose from 850,000 to 1.5 million [National Center for Education Statistics July 2004, Dec 2008]. For many of these families, math and science are difficult subjects to teach because the parents do not know how to convey the ideas to their children in an engaging way. This is made more difficult because the parents themselves are not engaged. Classroom demonstrations and hands-on activities are a very effective ways to teach science concepts while showing that science itself can be fun and exciting but demonstrations do not typically include homeschooling families and in many cases doing the experiments on their own is not an option due to availability and cost of the materials. In this presentation we will discuss some ways to make demonstrations and hands-on activities more accessible to homeschooling families as well as looking at various ways of overcoming difficulties when teaching science in the home. References Princiotta, D., Bielick, S., and Chapman, C. (2004). 1.1 Million Homeschooled Students in the United States in 2003 (NCES 2004-115). National Center for Education Statistics, Institute of Education Sciences, U.S. Department of Education. Washington, D.C. Bielick S. (2008) 1.5 Million Homeschooled Students in the United States in 2007 (NCES 2009-030). National Center for Education Statistics, Institute of Education Sciences, U.S. Department of Education. Washington, D.C.

  4. Creation Science Is Not Science.

    ERIC Educational Resources Information Center

    Ruse, Michael

    1982-01-01

    Discusses salient characteristics of scientific enterprise including laws (natural regularities), explanation and prediction, testability, confirmation, and falsifiability, tentativeness, and professional integrity. Argues that "creation-science" lacks each of these essential characteristics. (JN)

  5. Science Fairs for Science Literacy

    NASA Astrophysics Data System (ADS)

    Mackey, Katherine; Culbertson, Timothy

    2014-03-01

    Scientific discovery, technological revolutions, and complex global challenges are commonplace in the modern era. People are bombarded with news about climate change, pandemics, and genetically modified organisms, and scientific literacy has never been more important than in the present day. Yet only 29% of American adults have sufficient understanding to be able to read science stories reported in the popular press [Miller, 2010], and American students consistently rank below other nations in math and science [National Center for Education Statistics, 2012].

  6. Fantastic Physics: Developing an Early Interest in Science. A Preschool Science Curriculum.(4 Year Old Curriculum).

    ERIC Educational Resources Information Center

    Summer, Gail L.; Giovannini, Kathleen

    Using hands-on activities and the "Plan, Do, Review" approach, this physics curriculum for 4-year-olds is designed to develop an early interest in and enthusiasm for science and to excite children about learning in general. The curriculum is designed to be implemented biweekly in preschool or child care programs but may also be presented at a

  7. Detecting cracked rotors using auxiliary harmonic excitation

    NASA Astrophysics Data System (ADS)

    Sawicki, Jerzy T.; Friswell, Michael I.; Kulesza, Zbigniew; Wroblewski, Adam; Lekki, John D.

    2011-03-01

    Cracked rotors are not only important from a practical and economic viewpoint, they also exhibit interesting dynamics. This paper investigates the modelling and analysis of machines with breathing cracks, which open and close due to the self-weight of the rotor, producing a parametric excitation. After reviewing the modelling of cracked rotors, the paper analyses the use of auxiliary excitation of the shaft, often implemented using active magnetic bearings to detect cracks. Applying a sinusoidal excitation generates response frequencies that are combinations of the rotor spin speed and excitation frequency. Previously this system was analysed using multiple scales analysis; this paper suggests an alternative approach based on the harmonic balance method, and validates this approach using simulated and experimental results. Consideration is also given to some issues to enable this approach to become a robust condition monitoring technique for cracked shafts.

  8. Ultrafast optical excitation of magnetic skyrmions.

    PubMed

    Ogawa, N; Seki, S; Tokura, Y

    2015-01-01

    Magnetic skyrmions in an insulating chiral magnet Cu2OSeO3 were studied by all-optical spin wave spectroscopy. The spins in the conical and skyrmion phases were excited by the impulsive magnetic field from the inverse-Faraday effect, and resultant spin dynamics were detected by using time-resolved magneto-optics. Clear dispersions of the helimagnon were observed, which is accompanied by a distinct transition into the skyrmion phase, by sweeping temperature and magnetic field. In addition to the collective excitations of skyrmions, i.e., rotation and breathing modes, several spin precession modes were identified, which would be specific to optical excitation. The ultrafast, nonthermal, and local excitation of the spin systems by photons would lead to the efficient manipulation of nano-magnetic structures. PMID:25897634

  9. Nuclear excitation by electronic transition (NEET).

    SciTech Connect

    Ahmad, I.; Dunford, R. W.; Esbensen, H.; Gemmell, D. S.; Kanter, E. P.; Kraessig, B.; Ruett, U.; Southworth, S. H.

    1999-04-28

    We present a report on recent measurements using the Advanced Photon Source at Argonne National Laboratory to explore the phenomenon of Nuclear Excitation by Electronic Transition (NEET) in the {sup 189}Os atomic/nuclear system.

  10. Fear, excitement, and financial risk-taking.

    PubMed

    Lee, Chan Jean; Andrade, Eduardo B

    2015-01-01

    Can fear trigger risk-taking? In this paper, we assess whether fear can be reinterpreted as a state of excitement as a result of contextual cues and promote, rather than discourage, risk-taking. In a laboratory experiment, the participants' emotional states were induced (fear vs. control), followed by a purportedly unrelated financial task. The task was framed as either a stock market investment or an exciting casino game. Our results showed that incidental fear (vs. control) induced risk-averse behaviour when the task was framed as a stock investment decision. However, fear encouraged risk-taking when the very same task was framed as an exciting casino game. The impact of fear on risk-taking was partially mediated by the excitement felt during the financial task. PMID:24661027

  11. Magnetic Excitation for Spin Vibration Testing

    NASA Technical Reports Server (NTRS)

    Johnson, Dexter; Mehmed, Oral; Brown, Gerald V.

    1997-01-01

    The Dynamic Spin Rig Laboratory (DSRL) at the NASA Lewis Research Center is a facility used for vibration testing of structures under spinning conditions. The current actuators used for excitation are electromagnetic shakers which are configured to apply torque to the rig's vertical rotor. The rotor is supported radially and axially by conventional bearings. Current operation is limited in rotational speed, excitation capability, and test duration. In an effort to enhance its capabilities, the rig has been initially equipped with a radial magnetic bearing which provides complementary excitation and shaft support. The new magnetic feature has been used in actual blade vibration tests and its performance has been favorable. Due to the success of this initial modification further enhancements are planned which include making the system fully magnetically supported. This paper reports on this comprehensive effort to upgrade the DSRL with an emphasis on the new magnetic excitation capability.

  12. On Oscillators in Phyllosilicate Excitable Automata

    NASA Astrophysics Data System (ADS)

    Adamatzky, Andrew

    2013-06-01

    Phyllosilicate is a sheet of silicate tetrahedra bound by basal oxygens. A phyllosilicate excitable automaton is a regular network of finite state machines, which mimics structure of a silicate sheet. A node of the silicate sheet is an automaton, which takes resting, excited and refractory states, and updates its state in discrete time depending on a sum of excited states of its three (silicon automata) or six (oxygen automata) closest neighbors. Oscillator is a localized compact configuration of nonquiescent states which undergoes finite growth and modification but returns to its original state in a finite number of steps. We show that phyllosilicate excitable automata exhibit waves and oscillating localizations (oscillators) dynamics. Basic types of oscillators are classified and characterized.

  13. Acoustics of Excited Jets: A Historical Perspective

    NASA Technical Reports Server (NTRS)

    Brown, Cliffard A.

    2005-01-01

    The idea that a jet may be excited by external forcing is not new. The first published demonstration of a jet responding to external pressure waves occurred in the mid-1800's. It was not, however, until the 1950's, with the advent of commercial jet aircraft, that interest in the subject greatly increased. Researchers first used excited jets to study the structure of the jet and attempt to determine the nature of the noise sources. The jet actuators of the time limited the range (Reynolds and Mach numbers) of jets that could be excited. As the actuators improved, more realistic jets could be studied. This has led to a better understanding of how jet excitation may be used not only as a research tool to understand the flow properties and noise generation process, but also as a method to control jet noise.

  14. Inclination Excitation in Extrasolar Planetary Systems

    NASA Astrophysics Data System (ADS)

    Becker, Juliette; Adams, Fred C.

    2015-01-01

    The Kepler Mission has detected dozens of planetary systems with more than four transiting planets. This sample provides a collection of planetary systems with little or no excited inclination between the inferred orbits. This present study examines the magnitude and efficacy of three potential mechanisms for exciting orbital inclination in these systems: self-excitation of orbital inclination in initially coplanar planetary systems, perturbations by larger bodies within the planetary systems, and perturbations by massive bodies external to the systems. For each of these mechanisms, we determine the regime(s) of parameter space for which orbital inclination excitation is effective. This work provides constraints on the properties (masses and orbital elements) of possible additional bodies in observed planetery systems, and on their dynamical history. One interesting application is to consider the relative size of the external perturbations both in and out of clusters.

  15. Collisional Excitation Rates in the ISM

    NASA Astrophysics Data System (ADS)

    Dubernet, M. L.; Valiron, P.; Daniel, F.; Grosjean, A.; Lique, F.; Feautrier, N.; Spielfiedel, A.; Faure, A.; Wernli, M.; Wiesenfeld, L.; Rist, C.

    2005-08-01

    The paper focuses on collisional excitation rates of molecules by He and H2 relevant to the interstellar medium. It discusses currently available data, presents very recent work and outlines new work being carried out by various teams.

  16. Effective local potentials for excited states

    NASA Astrophysics Data System (ADS)

    Staroverov, Viktor N.; Glushkov, Vitaly N.

    2010-12-01

    The constrained variational Hartree-Fock method for excited states of the same symmetry as the ground state [Chem. Phys. Lett. 287, 189 (1998)] is combined with the effective local potential (ELP) method [J. Chem. Phys. 125, 081104 (2006)] to generate Kohn-Sham-type exact-exchange potentials for singly excited states of many-electron systems. Illustrative examples include the three lowest 2S states of the Li and Na atoms and the three lowest 3S states of He and Be. For the systems studied, excited-state ELPs differ from the corresponding ground-state potentials in two respects: They are less negative and have small additional "bumps" in the outer electron region. The technique is general and can be used to approximate excited-state exchange-correlation potentials for other orbital-dependent functionals.

  17. Nonlinear excited waves on the interventricular septum

    NASA Astrophysics Data System (ADS)

    Bekki, Naoaki; Harada, Yoshifumi; Kanai, Hiroshi

    2012-11-01

    Using a novel ultrasonic noninvasive imaging method, we observe some phase singularities in propagating excited waves on a human cardiac interventricular septum (IVS) for a healthy young male. We present a possible physical model explaining one-dimensional dynamics of phase singularities in nonlinearly excited waves on the IVS. We show that at least one of the observed phase singularities in the excited waves on the IVS can be explained by the Bekki-Nozaki hole solution of the complex Ginzburg-Landau equation without any adjustable parameters. We conclude that the complex Ginzburg-Landau equation is such a suitable model for one-dimensional dynamics of cardiac phase singularities in nonlinearly excited waves on the IVS.

  18. The aeronomy of vibrationally excited ozone

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.; Allen, J. E., Jr.

    1980-01-01

    Theoretical calculations show that above 80 km in the earth's atmosphere the production of vibrationally excited ozone by chemical processes leads to number densities which are usually larger than those expected for local thermodynamic equilibrium. Quenching of highly excited molecules produced in O+O2+M, O3+M provided a significant source of the lower lying states above the mesopause while the 9.6 microns emission of O3 (0,0,1) was a major sink. Analysis of available laboratory results implied that reactions involving excited ozone play a significant role in the global ozone balance despite the relatively small abundance of the molecule. However, this effect is implicit in many of the rate coefficients currently used in stratospheric calculations. In the upper mesosphere and lower thermosphere, where the excited state populations differ from those for thermal equilibrium, published reaction rate data are not necessarily applicable to aeronomic calculations.

  19. Excitation with Effective Subcycle Laser Pulses

    NASA Astrophysics Data System (ADS)

    Marceau, C.; Gingras, G.; Witzel, B.

    2013-11-01

    We have used laser pulses with a temporally shaped polarization to demonstrate the multiphoton excitation of the xenon 5g state within a subcycle of a laser pulse. Our polarization gated laser pulses are composed of circularly polarized sections at the leading and trailing edges of the pulse and of an experimentally defined linearly polarized central part. Only the linear part (the gate) of the pulse can excite neutral xenon in the 5g state. The transition cannot be driven with circularly polarized light because the number of photons needed would cause a violation of selection rules for the change of the magnetic quantum number. We show that the linearly polarized central part can be reduced to a subcycle pulse. This allows us to study excitation with an effective pulse as short as 2.3 fs at 800 nm. Electron imaging spectroscopy has been used to visualize the presence of excited states as a function of the pulse duration of the gate.

  20. Mode Selective Excitation Using Coherent Control Spectroscopy

    SciTech Connect

    Singh, Ajay K.; Konradi, Jakow; Materny, Arnulf; Sarkar, Sisir K.

    2008-11-14

    Femtosecond time-resolved coherent anti-Stokes Raman scattering (fs-CARS) gives access to ultrafast molecular dynamics. However, femtosecond laser pulses are spectrally broad and therefore coherently excite several molecular modes. While the temporal resolution is high, usually no mode-selective excitation is possible. This paper demonstrates the feasibility of selectively exciting specific molecular vibrations in solution phase with shaped fs laser excitation using a feedback-controlled optimization technique guided by an evolutionary algorithm. This approach is also used to obtain molecule-specific CARS spectra from a mixture of different substances. The optimized phase structures of the fs pulses are characterized to get insight into the control process. Possible applications of the spectrum control are discussed.

  1. Delivering Science from Big Data

    NASA Astrophysics Data System (ADS)

    Quinn, Peter Joseph

    2015-08-01

    The SKA will be capable of producing a stream of science data products that are Exa-scale in terms of their storage and processing requirements. This Google-scale enterprise is attracting considerable international interest and excitement from within the industrial and academic communities. In this paper we examine the data flow, storage and processing requirements of a number of key SKA survey science projects to be executed on the baseline SKA1 configuration. Based on a set of conservative assumptions about trends for HPC and storage costs, and the data flow process within the SKA Observatory, it is apparent that survey projects of the scale proposed will potentially drive construction and operations costs beyond the current anticipated SKA1 budget. This implies a sharing of the resources and costs to deliver SKA science between the community and what is contained within the SKA Observatory. A similar situation was apparent to the designers of the LHC more than 10 years ago. We propose that it is time for the SKA project and broader community to consider the effort and process needed to design and implement a distributed science data system that leans on the lessons of other projects and looks to recent developments in Cloud technologies to ensure an affordable, effective and global achievement of science goals.

  2. Fast pulsed excitation wiggler or undulator

    DOEpatents

    van Steenbergen, Arie

    1990-01-01

    A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.

  3. College-industry alliances improving science education in Kansas

    SciTech Connect

    Singh, S.P.; Moore, J.; Palubicki, S.

    1994-12-31

    Kansas Newman College`s investigate laboratory approach and its partnership with local industries has been motivating precollege students into science since 1990. The Vulcan Chemical Company in Wichita supported our Investigative Summer Science Program for high school juniors where we make science fun and exciting through exploration and testing of ideas, broaden their scientific interests, foster independent scholarship, and with active involvement of community scientists, make them aware of career opportunities and challenges in sciences. Upon completion, 80% to 94% of the participants became interested in pursuing science in college. Our second approach has been to encourage pre-college faculty to have their students present science projects at the annual meeting of Kansas Junior Academy of Science. The Metropolitan Life Foundation has been underwriting all the expenses for promoting participation and hosting of the annual meeting since 1987. The number of science projects/papers has increased from 11 in 1987 to 43 in 1993.

  4. ISKAF2010 Science Meeting

    NASA Astrophysics Data System (ADS)

    Radio astronomy - in its broadest sense from metre to sub-millimetre wavelengths - is making a major leap forward. Triggered by the efforts being made towards realising the Square Kilometre Array (SKA), a number of new facilities, or major upgrades of existing facilities, are coming on-line, bringing new excitement among radio astronomers and revitalising the interest of the astronomical community in general. The fantastic capabilities of these new facilities will revolutionise the way we do radio astronomy. The use of innovative technology solutions (including new software approaches and calibration algorithms) is expected to significantly enhance the performance of this new generation of radio telescopes. The associated advances in sensitivity, field-of-view, frequency range and spectral resolution guarantees that new and exciting science will be conducted. We are now truly entering a new golden age for radio astronomy. And this is only the beginning! The meeting takes its inspiration from the opening of the LOw Frequency ARray (LOFAR) but there are many other telescopes or upgrades that are now coming online. These include the E-VLA, e-MERLIN, e-VLBI, MWA, PAPER, ATA, eSMA, EMBRACE, SCUBA-2, APEX, IRAM, Yebes and ATCA (CABB). Some of these facilities are now beginning to produce their first results. This meeting aims to provide an overview of these first successes and indeed struggles(!), and highlight the future perspective and longer term goals of our community. These initial results will give a first taste of the science (and the challenges) that we will enjoy with the SKA. Several major elements of new telescopes like MEERKAT, ALMA, ASKAP, APERTIF, LWA, SRT and FAST are also expected to be producing some initial technical results around this time - these will also be covered in the programme of the meeting. In summary, we encourage presentations on results that use new or recently upgraded telescopes, or results that use new challenging techniques or address science issues that will be fully explored by the new generation of radio telescopes. The meeting is part of a week-long series of events organised around the opening of LOFAR and the International SKA Forum 2010. The LOFAR opening will take place on Saturday 12 June, while the Forum is scheduled on Tuesday 15 June. The (somewhat unusual) schedule of the "A new golden age for radio astronomy" meeting has been made in order to give the participants an opportunity to attend all of these events. On Monday June 14th science funding agencies from around the globe will meet to discuss how they will accommodate the SKA (Agencies SKA Group). On the same day industrial partners will join in a workshop to discuss the opportunities of the SKA, not only for science and industry but also for the society as a whole in the Connect Industry Science and Society Workshop (CISS). The venue for all of the above meetings will be the luxury resort "Hof van Saksen" located south of the city of Assen. The absolute climax of the week will be the International SKA Forum on June 15th at the TT-hal in Assen where high level politicians, top scientists, major industries, policy makers and candidate sites for the SKA will meet on `SKA beyond Astronomy'.

  5. Excitations in Liquid HELIUM-4 Films.

    NASA Astrophysics Data System (ADS)

    Tymczak, Christopher John

    1995-01-01

    We use the hypernetted chain (HNC) variational theory for inhomogeneous systems to study the excitations in ^4He films adsorbed to a graphite substrate. The first part of this dissertation describes the HNC variational theory and how it is used to calculate the physical properties of ^4He films. We then extend the theory to describe excitations in these films. The simplest implementation of the theory, which assumes time-dependent one-body correlations only, is the generalization of Feynman's theory of excitations to inhomogeneous geometries. We then include time-dependent fluctuations of the two-body correlations. This leads to two important improvements of the theory. First, the predictions of the new theory agree significantly better with experiments. Second, since the now theory also allows for damping effects, we can calculate the lifetimes of individual excitations. Insight can be gained into the physical nature of the film's excited states by studying the transition densities and the probability currents. We describe how these quantities can be calculated within the generalized theory of excitations, and present results for mono-, double -, and triple-layer films.

  6. Literacy, science, and science education

    NASA Astrophysics Data System (ADS)

    McVittie, Janet Elizabeth

    In examining the connections between literacy, science and science education, I laid out a number of questions. For example, what sorts of literate tools might facilitate writing to learn, and do children who are just becoming literate use these tools? I then examined the writing of children in science class in an attempt to determine if their writing can indeed facilitate their learning. The results of this research could help teachers make decisions about the use of writing in the learning of science. The kinds of literate tools I identified as being potentially helpful were transitionals---those words or grammatical devices which demonstrate how ideas are connected. Also, I suggested that data tables, sentences and paragraphs were also useful for students to learn. I found that grade 5/6 students used a wide range of literate tools, but that they were much more competent with those tools which were both oral and literate than those which could only be used for writing (punctuation, sentences, paragraphs, and data tables). When I attempted to determine if the children used their writing to learn, I found very little evidence that this was certainly so. However, there was some evidence that paragraphs had the potential to create a "dialogue" between student writing and thinking, so the students could make more explicit connections between science ideas. Lastly, I noticed certain gender difference in the classroom. Because of this, I contrasted the writing of the girls with the writing of the boys. I learned the girls were generally much more capable writers than the boys. More interesting, however, was that the girls generally attempted to explain their science concepts in different ways than did the boys. The girls were more likely to rely on their own reasoning, whereas the boys were more likely to persist in using culturally created science explanations. The research findings have important implications for analyzing students' learning and for finding ways to facilitate learning for both girls and boys.

  7. Antecedents of two-photon excitation laser scanning microscopy.

    PubMed

    Masters, Barry R; So, Peter T C

    2004-01-01

    In 1931, Maria Göppert-Mayer published her doctoral dissertation on the theory of two-photon quantum transitions (two-photon absorption and emission) in atoms. This report describes and analyzes the theoretical and experimental work on nonlinear optics, in particular two-photon excitation processes, that occurred between 1931 and the experimental implementation of two-photon excitation microscopy by the group of Webb in 1990. In addition to Maria Göppert-Mayer's theoretical work, the invention of the laser has a key role in the development of two-photon microscopy. Nonlinear effects were previously observed in different frequency domains (low-frequency electric and magnetic fields and magnetization), but the high electric field strength afforded by lasers was necessary to demonstrate many nonlinear effects in the optical frequency range. In 1978, the first high-resolution nonlinear microscope with depth resolution was described by the Oxford group. Sheppard and Kompfner published a study in Applied Optics describing microscopic imaging based on second-harmonic generation. In their report, they further proposed that other nonlinear optical effects, such as two-photon fluorescence, could also be applied. However, the developments in the field of nonlinear optical stalled due to a lack of a suitable laser source. This obstacle was removed with the advent of femtosecond lasers in the 1980s. In 1990, the seminal study of Denk, Strickler, and Webb on two-photon laser scanning fluorescence microscopy was published in Science. Their paper clearly demonstrated the capability of two-photon excitation microscopy for biology, and it served to convince a wide audience of scientists of the potential capability of the technique. PMID:14677127

  8. Future NASA Earth Science Missions

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.

    2005-01-01

    With the launch of the last Earth Observation System (EOS) Missions, Aura, NASA now has a new fleet of 13+ highly capable remote sensing spacecraft orbiting the earth. Results from these missions are showing us the earth system as never seen before. But, what are the new challenges in understanding the Earth in an era of rapid change? In this talk I will outline some of the exciting results from the EOS missions and pull back the curtain on NASA's future earth science missions.

  9. Communicating Science through Exhibitions

    NASA Astrophysics Data System (ADS)

    Dusenbery, P.; Harold, J.; Morrow, C.

    It is critically important for the public to better understand the scientific process. Museum exhibitions are an important part of informal science education that can effectively reach public audiences as well as school groups. They provide an important gateway for the public to learn about compelling scientific endeavors. There are many ways for scientists to help develop science exhibitions. The Space Science Institute (SSI) is a national leader in producing traveling science exhibitions and their associated educational programming (i.e. interactive websites, educator workshops, public talks, instructional materials). Two of its exhibitions, Space Weather Center and MarsQuest, are currently on tour. Another exhibition, Alien Earths, is in development. The Space Weather Center was developed in partnership with various research missions at NASA's Goddard Space Flight Center. MarsQuest is a 5000 square-foot traveling exhibition. The exhibit's second 3-year tour began this January at the Detroit Science Center. It is enabling millions of Americans to share in the excitement of the scientific exploration of Mars and to learn more about their own planet in the process. The 3,000 square-foot traveling exhibition, called Alien Earths, will bring origins-related research and discoveries to students and the American public. Alien Earths has four interrelated exhibit areas: Our Place in Space, Star Birth, PlanetQuest, and Search for Life. Exhibit visitors will explore the awesome events surrounding the birth of stars and planets; they will join scientists in the hunt for planets outside our solar system including those that may be in ``habitable zones'' around other stars; and finally they will be able to learn about how scientists are looking for signs of life beyond Earth. Besides the exhibits, SSI is also developing interactive web sites based on exhibit themes. New technologies are transforming the Web from a static medium to an interactive environment with tremendous potential for informal education and inquiry-based investigations. This talk will focus on the development of the MarsQuest and Alien Earths exhibitions and their associated education programs.

  10. The Science For Our Schools (SFOS) Program

    NASA Astrophysics Data System (ADS)

    Terebey, S.; Mayo, D.; Strauss, J.

    2004-12-01

    The Science For Our Schools (SFOS) program at California State University at Los Angeles places graduate students from Astronomy, Biology, Chemistry, Geology, and Physics with science teachers in secondary classrooms throughout the Los Angeles area. The program implements activities and demonstrations based on California's new science content standards. Graduate Fellows act as science communicators to bring the excitement of scientific research to high school classrooms. Fellows are partnered with highly experienced science teachers in seven different middle and high schools, most of which have high minority enrollment and large numbers of students from low-income families. In addition to curriculum development, our Fellows plan field trips, scout funding opportunities, facilitate lab equipment purchases, and help organize special events such as science fairs and "Ask a Scientist" nights. SFOS Fellows and PI's meet weekly to exchange ideas and experiences, to review current science education literature, and to preview curriculum developed for our middle and high school science classrooms. All SFOS participants gather at quarterly workshops to share the results of program activities through presentations and discussions. We thank the National Science Foundation for funding through the GK-12 program.

  11. Professionals and Emerging Scientists Sharing Science

    NASA Technical Reports Server (NTRS)

    Graff, P. V.; Allen, J. S.; Tobola, K.

    2010-01-01

    The Year of the Solar System (YSS) celebration begins in the fall of 2010. As YSS provides a means in which NASA can inspire members of the public about exciting missions to other worlds in our solar system, it is important to remember these missions are about the science being conducted and new discoveries being made. As part of the Year of the Solar System, Astromaterials Research and Exploration Science (ARES) Education, at the NASA Johnson Space Center, will infuse the great YSS celebration within the Expedition Earth and Beyond Program. Expedition Earth and Beyond (EEAB) is an authentic research program for students in grades 5-14 and is a component of ARES Education. Students involved in EEAB have the opportunity to conduct and share their research about Earth and/or planetary comparisons. ARES Education will help celebrate this exciting Year of the Solar System by inviting scientists to share their science. Throughout YSS, each month will highlight a topic related to exploring our solar system. Additionally, special mission events will be highlighted to increase awareness of the exciting missions and exploration milestones. To bring this excitement to classrooms across the nation, the Expedition Earth and Beyond Program and ARES Education will host classroom connection events in which scientists will have an opportunity to share discoveries being made through scientific research that relate to the YSS topic of the month. These interactive presentations will immerse students in some of the realities of exploration and potentially inspire them to conduct their own investigations. Additionally, scientists will share their own story of how they were inspired to pursue a STEM-related career that got them involved in exploration. These career highlights will allow students to understand and relate to the different avenues that scientists have taken to get where they are today. To bring the sharing of science full circle, student groups who conduct research by participating in Expedition Earth and Beyond, will also have the opportunity to virtually share their research. These virtual team presentations will allow these emerging scientists to celebrate their own exploration, and in doing so, contribute to the excitement of the Year of the Solar System. As the public joins NASA in the celebration of YSS, students across the nation will not only be excited by the science and discoveries being made, but will prime themselves with experience to perhaps someday become the new leaders in science, discovery, and NASA.

  12. Tailoring Dye-sensitized Upconversion Nanoparticles Excitation Bands towards Excitation Wavelength Selective Imaging

    PubMed Central

    Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; Zhang, Yuanwei; Li, Zhanjun; Chen, Teresa; Liu, Yi; Duan, Chunying; Shen, Jie; Punjabi, Amol; Han, Gang

    2015-01-01

    One of key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs. PMID:26499208

  13. Tailoring dye-sensitized upconversion nanoparticle excitation bands towards excitation wavelength selective imaging.

    PubMed

    Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; Zhang, Yuanwei; Li, Zhanjun; Chen, Teresa; Liu, Yi; Duan, Chunying; Shen, Jie; Punjabi, Amol; Han, Gang

    2015-11-28

    One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs. PMID:26499208

  14. Nonlinear parametrically excited vibration and active control of gear pair system with time-varying characteristic

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Wang, Jin-Jin; Liu, Jin-Jie; Li, Ya-Qian

    2015-10-01

    In the present work, we investigate the nonlinear parametrically excited vibration and active control of a gear pair system involving backlash, time-varying meshing stiffness and static transmission error. Firstly, a gear pair model is established in a strongly nonlinear form, and its nonlinear vibration characteristics are systematically investigated through different approaches. Several complicated phenomena such as period doubling bifurcation, anti period doubling bifurcation and chaos can be observed under the internal parametric excitation. Then, an active compensation controller is designed to suppress the vibration, including the chaos. Finally, the effectiveness of the proposed controller is verified numerically. Project supported by the National Natural Science Foundation of China (Grant No. 61104040), the Natural Science Foundation of Hebei Province, China (Grant No. E2012203090), and the University Innovation Team of Hebei Province Leading Talent Cultivation Project, China (Grant No. LJRC013).

  15. Science Notes.

    ERIC Educational Resources Information Center

    Shaw, G. W.; And Others

    1989-01-01

    Provides a reading list for A- and S-level biology. Contains several experiments and demonstrations with topics on: the intestine, bullock corneal cells, valences, the science of tea, automated hydrolysis, electronics characteristics, bromine diffusion, enthalpy of vaporization determination, thermometers, pendulums, hovercraft, Bernoulli fluid…

  16. Kaleidoscope Science.

    ERIC Educational Resources Information Center

    Janes, Patricia

    2002-01-01

    Presents a collection of science activities that have elementary students investigate how color can trick the eye and the brain. The activities involve working with contrasting colors, creating a rainbow, and exploring the connection between colors and words. An instructor reproducible features two color activities. (SM)

  17. Science Notes.

    ERIC Educational Resources Information Center

    Shaw, G. W.; And Others

    1989-01-01

    Provides a reading list for A- and S-level biology. Contains several experiments and demonstrations with topics on: the intestine, bullock corneal cells, valences, the science of tea, automated hydrolysis, electronics characteristics, bromine diffusion, enthalpy of vaporization determination, thermometers, pendulums, hovercraft, Bernoulli fluid

  18. Skeptical Science.

    ERIC Educational Resources Information Center

    Scott, Alan J.; Barnhart, Carolyn M.; Parejko, Ken S.; Schultz, Forrest S.; Schultz, Steven E.

    2001-01-01

    Discusses the legitimacy of teaching about astrology, extrasensory perception, UFOs, touch therapy, cloning dinosaurs, or any other unusual claims in the classroom. Suggests that bringing unusual claims to the science classroom is an opportunity to motivate students in the principles of scientific thought. (SAH)

  19. Talking Science

    ERIC Educational Resources Information Center

    Eley, Alison

    2011-01-01

    The Talking Science project initially involved three secondary schools and eight of their feeder primary schools in the London Borough of Richmond Upon Thames. The project created, trialled and evaluated a set of key stage 2/3 transition materials for children moving from primary to secondary school, using argument as a teaching and learning

  20. Science Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1986

    1986-01-01

    Describes activities, games, experiments, demonstrations, and computer-oriented exercises in all science areas. Topics include energy flow through a marine ecosystem, using 2,4-dichlorophenoxyethanoic acid to demonstrate translocation in plants, use of the dichotomous key, use of leaf yeasts to monitor atmospheric pollution, and others. (JN)

  1. Brewing Science

    ERIC Educational Resources Information Center

    Pelter, Michael

    2006-01-01

    Following the brewing process from grain to glass, this course uses the biological and chemical principles of brewing to teach science to the nonscience major. Discussion of the scientific aspects of malting, mashing, fermentation, and the making of different beer styles is complemented by laboratory exercises that use scientific methods to

  2. Environmental Science

    ERIC Educational Resources Information Center

    Eads, Ewin A.

    1973-01-01

    Discusses implementation of an interdisciplinary bachelor of science degree program in Lamar University, Beaumont, with emphases upon the training of pollution and environmental quality control. Indicates that graduates' job opportunities are created by the enactment of recent laws for cleaner air and water. (CC)

  3. Cognitive Science.

    ERIC Educational Resources Information Center

    Cocking, Rodney R.; Mestre, Jose P.

    The focus of this paper is on cognitive science as a model for understanding the application of human skills toward effective problem-solving. Sections include: (1) "Introduction" (discussing information processing framework, expert-novice distinctions, schema theory, and learning process); (2) "Application: The Expert-Novice Paradigm as a Means

  4. Nuclear Science.

    ERIC Educational Resources Information Center

    Pennsylvania State Dept. of Education, Harrisburg. Bureau of Curriculum Services.

    This document is a report on a course in nuclear science for the high school curriculum. The course is designed to provide a basic but comprehensive understanding of the atom in the light of modern knowledge, and to show how people attempt to harness the tremendous energy liberated through fission and fusion reactions. The course crosses what are

  5. Science Notes.

    ERIC Educational Resources Information Center

    Talbot, Chris; And Others

    1991-01-01

    Twenty science experiments are presented. Topics include recombinant DNA, physiology, nucleophiles, reactivity series, molar volume of gases, spreadsheets in chemistry, hydrogen bonding, composite materials, radioactive decay, magnetism, speed, charged particles, compression waves, heat transfer, Ursa Major, balloons, current, and expansion of

  6. Science Journalism

    ERIC Educational Resources Information Center

    Polman, Joseph; Newman, Alan; Farrar, Cathy; Saul, E. Wendy

    2012-01-01

    Much of the National Science Education Standards (NRC 1996), aside from the inquiry and teaching sections, focus on content. The authors' call is instead to build standards that focus on what students need to be scientifically literate in 10 or 15 years. Although a basic understanding of important scientific concepts and an understanding of how

  7. Literary Science.

    ERIC Educational Resources Information Center

    Garrison, Megan R.

    2000-01-01

    Explains the use of literacy in science education. Uses "Silent Spring", a book on environmental issues, to encourage students to think about the role of water in balancing the earth's system and possible actions against environmental concerns. Creates an environment for students to discuss their knowledge on the use of the pesticide DDT. (YDS)

  8. Science Notes.

    ERIC Educational Resources Information Center

    Talbot, Chris; And Others

    1991-01-01

    Twenty science experiments are presented. Topics include recombinant DNA, physiology, nucleophiles, reactivity series, molar volume of gases, spreadsheets in chemistry, hydrogen bonding, composite materials, radioactive decay, magnetism, speed, charged particles, compression waves, heat transfer, Ursa Major, balloons, current, and expansion of…

  9. Nuclear Science.

    ERIC Educational Resources Information Center

    Pennsylvania State Dept. of Education, Harrisburg. Bureau of Curriculum Services.

    This document is a report on a course in nuclear science for the high school curriculum. The course is designed to provide a basic but comprehensive understanding of the atom in the light of modern knowledge, and to show how people attempt to harness the tremendous energy liberated through fission and fusion reactions. The course crosses what are…

  10. Redirecting science

    SciTech Connect

    Aaserud, F.

    1990-01-01

    This book contains the following chapters. Science policy and fund-raising up to 1934; The Copenhagen spirit at work, late 1920's to mid-1930s; The refugee problem, 1933 to 1935; Experimental biology, late 1920s to 1935; and Consolidation of the transition, 1935 to 1940.

  11. Animal Science.

    ERIC Educational Resources Information Center

    VanCleave, Janice

    2001-01-01

    Presents a set of hands-on, outdoor science experiments designed to teach elementary school students about animal adaptation. The experiments focus on: how color camouflage affects an insect population; how spiderlings find a home; and how chameleons camouflage themselves by changing color. (SM)

  12. Brewing Science

    ERIC Educational Resources Information Center

    Pelter, Michael

    2006-01-01

    Following the brewing process from grain to glass, this course uses the biological and chemical principles of brewing to teach science to the nonscience major. Discussion of the scientific aspects of malting, mashing, fermentation, and the making of different beer styles is complemented by laboratory exercises that use scientific methods to…

  13. Boundless Science

    NASA Astrophysics Data System (ADS)

    Spilhaus, F.

    2009-04-01

    Our science is critical to understanding the future prospects for life. The laboratory for natural sciences encompasses our planet and reaches into the solar system. The forces of nature respect no boundaries. But, we who try to understand these forces are handicapped by national, political, language, religious, and other concocted barriers. These barriers limit both our effectiveness as scientists and our ability to reach those outside our community who need to know what we have uncovered about our environment. An unencumbered worldwide scientific community has been an objective with limited successes for too long. Action began in earnest after the first world war with the formation of the various scientific Unions and ICSU. Fifty years later Keith Runcorn initiated another approach, when he proposed what quickly became EGS and which has grown and evolved with the merger with EUG. To be truly effective we need to communicate and share comfortably with colleagues worldwide. Personal relationships and trust are required. We count on a high level of ethical behavior within our community. We individually must also be constantly vigilant for the encroachment of the manmade barriers that have held back science through time immemorial. Our scientific organizations cannot achieve this alone. They will facilitate, however, the onus is on each of us to reach out and form interlocking informal communities, which will bring our whole planet-wide community together at many overlapping levels. When we achieve this community, our science will more bountiful and better address the needs of human society.

  14. Cognitive Science.

    ERIC Educational Resources Information Center

    Soni, P. Sarita, Ed.; Carmichael, Ann G., Ed.

    1993-01-01

    This theme issue features five articles profiling Indiana University faculty whose work on various campuses continues to broaden and advance knowledge about cognitive science. The articles in the journal are: "A Matter of Time" (Karen Grooms) which discusses the work of Robert F. Port; "Perceiving as a Complex System" (Tom Tierney) which profiles…

  15. Science First

    ERIC Educational Resources Information Center

    Comstock, Diane

    2005-01-01

    At the elementary level, when children learn best through hands-on activities, when is the best time to use literacy and make that connection to enhance learning? For teachers involved in Colorado Springs, Colorado, Science Teacher Enhancement Program Unifying the Pikes Peak Region, STEP-uP professional development program for teachers, it is

  16. Developing a Hyperspectral CLose UP Imager With UV Excitation (HyperCLUPI) for Mars Exploration

    NASA Astrophysics Data System (ADS)

    Barnes, D.; Josset, J.-L.; Coates, A.; Cousins, C.; Cockell, C.; Gunn, M.; Cross, R.; Langstaff, D.; Griffiths, A.; Josset, M.; Souchon, A.; Verhaeghe, A.; Grindrod, P.; Dartnell, L.

    2014-04-01

    The HyperCLUPI concept incorporates a high resolution, hyperspectral and conventional colour, variable focus camera system which can image targets with resolutions from meters to microns per pixel. The hyperspectral element in combination with fine-scale imaging and UV excitation provides a unique capability that would enable the remote and non-destructive detection and characterisation of priority Mars science targets such as hydrated mineral deposits and organic compounds; key to the search for life on Mars. Hyper-CLUPI offers new opportunities for planetary science given its spatial and spectral capabilities, and this paper describes elements of the ongoing HyperCLUPI development work.

  17. Manifesto of computational social science

    NASA Astrophysics Data System (ADS)

    Conte, R.; Gilbert, N.; Bonelli, G.; Cioffi-Revilla, C.; Deffuant, G.; Kertesz, J.; Loreto, V.; Moat, S.; Nadal, J.-P.; Sanchez, A.; Nowak, A.; Flache, A.; San Miguel, M.; Helbing, D.

    2012-11-01

    The increasing integration of technology into our lives has created unprecedented volumes of data on society's everyday behaviour. Such data opens up exciting new opportunities to work towards a quantitative understanding of our complex social systems, within the realms of a new discipline known as Computational Social Science. Against a background of financial crises, riots and international epidemics, the urgent need for a greater comprehension of the complexity of our interconnected global society and an ability to apply such insights in policy decisions is clear. This manifesto outlines the objectives of this new scientific direction, considering the challenges involved in it, and the extensive impact on science, technology and society that the success of this endeavour is likely to bring about.

  18. Science Curriculum Framework. Revised.

    ERIC Educational Resources Information Center

    Arkansas State Dept. of Education, Little Rock.

    This document presents the revised Arkansas Science Curriculum Framework (1999), which replaces the Science Curriculum Framework of 1994. Three strands--physical science systems, life science systems, and Earth science/space science systems--were identified using an integrated approach to provide guidance in the science curriculum. A glossary and

  19. Portraying Real Science in Science Communication

    ERIC Educational Resources Information Center

    van Dijk, Esther M.

    2011-01-01

    In both formal and informal settings, not only science but also views on the nature of science are communicated. Although there probably is no singular nature shared by all fields of science, in the field of science education it is commonly assumed that on a certain level of generality there is a consensus on many features of science. In this

  20. Science News and the Science Classroom

    ERIC Educational Resources Information Center

    McCullough, Laura

    2006-01-01

    Using "Science News" as a teaching tool promotes writing about science, talking about science, and broadening students' views about what science is. This article describes an ongoing assignment in which students choose one article from "Science News" each week and write a brief summary and explanation of why they picked that article. (Contains 1

  1. Science Literacy Circles: Big Ideas about Science

    ERIC Educational Resources Information Center

    Devick-Fry, Jane; LeSage, Teresa

    2010-01-01

    Science literacy circles incorporate the organization of both science notebooks and literature circles to help K-8 students internalize big ideas about science. Using science literacy circles gives students opportunities to engage in critical thinking as they inductively develop understanding about science concepts. (Contains 1 table and 7

  2. Science Goals for an All-sky Viewing Observatory in X-rays

    NASA Astrophysics Data System (ADS)

    Remillard, R. A.; Levine, A. M.; Morgan, E. H.; Bradt, H. V.

    2003-03-01

    We describe a concept for a NASA SMEX Mission that will provide a comprehensive investigation of cosmic explosions. These range from the short flashes at cosmological distances in Gamma-ray bursts, to the moments of relativistic mass ejections in Galactic microquasars, to the panorama of outbursts used to identify the stellar-scale black holes in our Galaxy. With an equatorial launch, an array of 31 cameras can cover 97% of the sky with an average exposure efficiency of 65%. Coded mask cameras with Xe detectors (1.5-12 keV) are chosen for their ability to distinguish thermal and non-thermal processes, while providing high throughput and msec time resolution to capture the detailed evolution of bright events. This mission, with 1' position accuracy, would provide a long-term solution to the critical needs for monitoring services for Chandra and GLAST, with possible overlap into the time frame for Constellation-X. The sky coverage would create additional science opportunities beyond the X-ray missions: "eyes" for LIGO and partnerships for time-variability with LOFAR and dedicated programs at optical observatories. Compared to the RXTE ASM, AVOX offers improvements by a factor of 40 in instantaneous sky coverage and a factor of 10 in sensitivity to faint X-ray sources (i.e. to 0.8 mCrab at 3 sigma in 1 day).

  3. Highlighting Your Science to NASA

    NASA Astrophysics Data System (ADS)

    Sharkey, C.

    2003-12-01

    An effort is underway to provide greater visibility within NASA headquarters, and to those who provide funding to NASA, of the outstanding work that is being performed by scientists involved in the Solar System Exploration Research and Analysis Programs, most of whom are DPS members. In support of this effort, a new feature has been developed for the NASA Headquarters Solar System Exploration Division web site whereby researchers can provide a synopsis of their current research results. The site (http://solarsystem.nasa.gov/spotlight/ - Username: your email address Password: sse) is an online submission area where NASA-funded scientists can upload the results of their research. There they provide their contact information, briefly describe their research, and upload any associated images or graphics. The information is available to a limited number of reviewers and writers at JPL. Each month, one researcher's work will be chosen as a science spotlight. After a writer interviews the scientist, a brief Power Point presentation that encapsulates their work will be given to Dr. Colleen Hartman at NASA headquarters. She will then present the exciting findings to Associate Administrator for Space Science, Dr. Ed Weiler. The information from some of these highlights can serve as a basis to bring Principal Investigators to NASA Headquarters for exposure to media through Space Science Updates on NASA television. In addition, the science results may also be incorporated into briefing material for the Office of Management and Budget and congressional staffers. Some spotlights will also be converted into feature stories for the Solar System Exploration website so the public, too, can learn about exciting new research. The site, http://solarsystem.nasa.gov/, is one of NASA's most visited. Over the past decade, there has been a trend of flat budgets for Research and Analysis activities. By giving more visibility to results of Solar System research, our goal is to encourage higher program funding levels from Congress and demonstrate the relevance of NASA research to the American public in general.

  4. Tone-excited jet: Theory and experiments

    NASA Technical Reports Server (NTRS)

    Ahuja, K. K.; Lepicovsky, J.; Tam, C. K. W.; Morris, P. J.; Burrin, R. H.

    1982-01-01

    A detailed study to understand the phenomenon of broadband jet-noise amplification produced by upstream discrete-tone sound excitation has been carried out. This has been achieved by simultaneous acquisition of the acoustic, mean velocity, turbulence intensities, and instability-wave pressure data. A 5.08 cm diameter jet has been tested for this purpose under static and also flight-simulation conditions. An open-jet wind tunnel has been used to simulate the flight effects. Limited data on heated jets have also been obtained. To improve the physical understanding of the flow modifications brought about by the upstream discrete-tone excitation, ensemble-averaged schlieren photographs of the jets have also been taken. Parallel to the experimental study, a mathematical model of the processes that lead to broadband-noise amplification by upstream tones has been developed. Excitation of large-scale turbulence by upstream tones is first calculated. A model to predict the changes in small-scale turbulence is then developed. By numerically integrating the resultant set of equations, the enhanced small-scale turbulence distribution in a jet under various excitation conditions is obtained. The resulting changes in small-scale turbulence have been attributed to broadband amplification of jet noise. Excellent agreement has been found between the theory and the experiments. It has also shown that the relative velocity effects are the same for the excited and the unexcited jets.

  5. Nuclear Excitation via Auger Transitions (NEAT)

    NASA Astrophysics Data System (ADS)

    Ward, Thomas; Emery, Guy; Rasmussen, John; Karwowski, Hugon; Castaneda, Carlos

    2008-10-01

    Triggering (prompt de-excitation) of isomeric states produced in a process of coupling nuclear excitations to atomic shells via Auger transitions (NEAT) is studied. In this resonant process the nuclear transition energy between the two states must be less than the Auger transition energy. This requires the emitted Auger electron energy and the exact on-resonance nuclear excitation share the Auger transition energy. NEAT is compared to other proposed processes of nuclear excitation produced by x-rays (NEET), by electron capture (NEEC) and bound internal conversion (BIC), all of which suffer from off-resonance nuclear excitation except in those accidental cases where the energies may coincide. Estimates of the total resonance strength will be given for the case of ^182mHf which has been extensively studied theoretically. A second case, ^189Os, where NEAT processes may contribute to the nuclear resonance fluorescence (NRF) of the ground state to the 5.8hr isomeric state will also be examined as a good case for experimental verification of the NEAT process.

  6. Targeting individual excited states in DMRG.

    NASA Astrophysics Data System (ADS)

    Dorando, Jonathan; Hachmann, Johannes; Kin-Lic Chan, Garnet

    2007-03-01

    The low-lying excited states of ?-conjugated molecules are important for the development of novel devices such as lasers, light-emitting diodes, photovoltaic cells, and field-effect transistors [1,2]. The ab-intio Density Matrix Renormalization Group (DMRG) provides a powerful way to explore the electronic structure of quasi-one-dimensional systems such as conjugated organic oligomers. However, DMRG is limited to targeting only low-lying excited states through state-averaged DMRG (SDMRG). There are several drawbacks; state-averaging degrades the accuracy of the excited states and is limited to at most a few of the low-lying states [3]. In this study, we present a new method for targeting higher individual excited states. Due to progress in the field of numerical analysis presented by Van Der Horst and others [4], we are able to target individual excited states of the Hamiltonian. This is accomplished by modifying the Jacobi-Davidson algorithm via a ``Harmonic Ritz'' procedure. We will present studies of oligoacenes and polyenes that compare the accuracy of SDMRG and Harmonic Davidson DMRG. [1] Burroughes, et al. , Nature 347, 539 (1990). [2] Shirota, J. Mater. Chem. 10, 1, (2000). [3] Ramasesha, Pati, Krishnamurthy, Shuai, Bredas, Phys. Rev. B. 54, 7598, (1997). [4] Bai, Demmel, Dongarra, Ruhe, Van Der Horst, Templates for the Solution of Algebraic Eigenvalue Problems, SIAM, 2000.

  7. Atmospheric Excitation of Planetary Normal Modes

    NASA Technical Reports Server (NTRS)

    Tanimoto, Toshiro

    2001-01-01

    The objectives of this study were to: (1) understand the phenomenon of continuous free oscillations of the Earth and (2) examine the idea of using this phenomenon for planetary seismology. We first describe the results on (1) and present our evaluations of the idea (2) in the final section. In 1997, after almost forty years since the initial attempt by Benioff et al, continuous free oscillations of the Earth were discovered. Spheroidal fundamental modes between 2 and 7 millihertz are excited continuously with acceleration amplitudes of about 0.3-0.5 nanogals. The signal is now commonly found in virtually all data recorded by STS-1 type broadband seismometers at quiet sites. Seasonal variation in amplitude and the existence of two coupled modes between the atmosphere and the solid Earth support that these oscillations are excited by the atmosphere. Stochastic excitation due to atmospheric turbulence is a favored mechanism, providing a good match between theory and data. The atmosphere has ample energy to support this theory because excitation of these modes require only 500-10000 W whereas the atmosphere contains about 117 W of kinetic energy. An application of this phenomenon includes planetary seismology, because other planets may be oscillating due to atmospheric excitation. The interior structure of planets could be learned by determining the eigenfrequencies in the continuous free oscillations. It is especially attractive to pursue this idea for tectonically quiet planets, since quakes may be too infrequent to be recorded by seismic instruments.

  8. Nonlinear excitations in inflationary power spectra

    NASA Astrophysics Data System (ADS)

    Miranda, Vinicius; Hu, Wayne; He, Chen; Motohashi, Hayato

    2016-01-01

    We develop methods to calculate the curvature power spectrum in models where features in the inflaton potential nonlinearly excite modes and generate high frequency features in the spectrum. The first nontrivial effect of excitations generating further excitations arises at third order in deviations from slow roll. If these further excitations are contemporaneous, the series can be resummed, showing the exponential sensitivity of the curvature spectrum to potential features. More generally, this exponential approximation provides a power spectrum template which nonlinearly obeys relations between excitation coefficients and whose parameters may be appropriately adjusted. For a large sharp step in the potential, it greatly improves the analytic power spectrum template and its dependence on potential parameters. For axionic oscillations in the potential, it corrects the mapping between the potential and the amplitude, phase and zero point of the curvature oscillations, which might otherwise cause erroneous inferences in for example the tensor-scalar ratio, formally even when that amplitude is 103 times larger than the slow-roll power spectrum. It also estimates when terms that produce double frequency oscillations that are usually omitted when analyzing data should be included. These techniques should allow future studies of high frequency features in the cosmic microwave background and large-scale structure to extend to higher amplitude and/or higher precision.

  9. Heliophysics Science

    NASA Astrophysics Data System (ADS)

    Austin, M.; Schrjver, K.; Siscoe, G. L.; Bhattacharjee, A.; Longcope, D. W.; Sojka, J. J.; Guhathakurta, M.

    2009-12-01

    HELIOPHYSICS SUMMER SCHOOLS: NASA Living With a Star and the University Corporation for Atmospheric Research, Visiting Scientist Programs sponsor the Heliophysics Summer Schools to build this new field of science. The series of summer schools, started in 2007, help graduate students and scientists learn and develop the science of heliophysics as a broad, coherent discipline that reaches in space from the Earth's troposphere to the depths of the Sun, and in time from the formation of the solar system to the distant future. The first three years of the school will result in three textbooks for use at universities worldwide. Subsequent years will both teach other generations of students and develop the complementary materials that support teaching of heliophysics at both graduate and undergraduate levels. Heliophysics is a developing scientific discipline integrating studies of the Sun’s variability, the surrounding heliosphere, and climatic environments. Over the past few centuries, our understanding of how the Sun drives space weather and climate on the Earth and other planets has advanced at an ever-increasing rate. The first textbook, (Heliophysics I Plasma Physics of the Local Cosmos, edited by Carolus J. Schrijver, Lockheed Martin and George L. Siscoe, Boston University) integrates such diverse topics for the first time as a coherent intellectual discipline. It emphasizes the physical processes coupling the Sun and Earth, allowing insights into the interaction of the solar wind and radiation with the Earth’s magnetic field, atmosphere and climate system. It provides a core resource for advanced undergraduates and graduates, and also constitutes a foundational reference for researchers in heliophysics, astrophysics, plasma physics, space physics, solar physics, aeronomy, space weather, planetary science and climate science. HELIOPHYSICS POSTDOCTORAL PROGRAM: Hosts and applicants are invited to apply to a new postdoctoral fellowship program designed to train the next generation of researchers in the emerging field of Heliophysics. Two major topics of focus for LWS are the science of space weather and of the Sun-climate connection. Preference will be given to applicants whose proposed research addresses one of these two foci; but any research program relevant to LWS will be considered. Since the goal of this fellowship program is to train Sun-Earth system researchers, preference will also be given to research projects that cross the traditional Heliophysics subdomains of the Sun, heliosphere, magnetosphere, and ionosphere/upper atmosphere, as well as Sun-climate investigations. Host institutions and mentoring scientists will play critical roles. Hosts may post information about their research on a central database for this program: www.vsp.ucar.edu/HeliophysicsScience.

  10. Science Shorts: "Sounds" Like Science

    ERIC Educational Resources Information Center

    Arnone, Kathryn; Morris, Bethany

    2014-01-01

    It seems each new school year brings its own opportunities to grow as an educator. As teachers in a STEM focused school that serves primarily at-risk students, the authors face a new challenge in rethinking their instruction to align with the "Next Generation Science Standards". This involves changing the focus of units previously taught

  11. The Science in Science Fiction.

    ERIC Educational Resources Information Center

    Nicholls, Peter, Ed.

    This 12-chapter book discusses the scientific facts behind the ideas included in the novels of Robert Heinlein, Isaac Asimov, Frederik Pohl, Arthur C. Clark and other science fiction writers. Areas explored in the first 11 chapters include: exploration of deep space; energy and exotic power sources; likelihood of extra-terrestrial life and the…

  12. The Science in Science Fiction.

    ERIC Educational Resources Information Center

    Nicholls, Peter, Ed.

    This 12-chapter book discusses the scientific facts behind the ideas included in the novels of Robert Heinlein, Isaac Asimov, Frederik Pohl, Arthur C. Clark and other science fiction writers. Areas explored in the first 11 chapters include: exploration of deep space; energy and exotic power sources; likelihood of extra-terrestrial life and the

  13. Science Centres and Science Learning.

    ERIC Educational Resources Information Center

    Rennie, Leonie J.; McClafferty, Terence P.

    1996-01-01

    Focuses on the interactive science center and its history over the last four decades. Traces the original idea to Francis Bacon. Recommends the use of cross-site studies to develop a model of learning in this setting. Contains 141 references. (DDR)

  14. Science Shorts: "Sounds" Like Science

    ERIC Educational Resources Information Center

    Arnone, Kathryn; Morris, Bethany

    2014-01-01

    It seems each new school year brings its own opportunities to grow as an educator. As teachers in a STEM focused school that serves primarily at-risk students, the authors face a new challenge in rethinking their instruction to align with the "Next Generation Science Standards". This involves changing the focus of units previously taught…

  15. Select Activities in the Regional Collaborative for Excellence in Science Teaching

    NASA Astrophysics Data System (ADS)

    Roberts, Jim

    2010-03-01

    The Regional Collaborative for Excellence in Science Teaching employs many avenues of approach to engage teachers and students in science. A group of ``milestone'' discoveries is used to show science teachers how science is driven by new and exciting principles, which look mysterious initially, but lead to good understanding when the underlying principle for the discovery is found. An exciting program for prospective college bound students was initiated in the fall of 2009 supported by a grant from the President's office at UNT. The results of some of these activities will be presented.

  16. Excited level populations and excitation kinetics of nonequilibrium ionizing argon discharge plasma of atmospheric pressure

    SciTech Connect

    Akatsuka, Hiroshi

    2009-04-15

    Population densities of excited states of argon atoms are theoretically examined for ionizing argon plasma in a state of nonequilibrium under atmospheric pressure from the viewpoint of elementary processes with collisional radiative model. The dependence of excited state populations on the electron and gas temperatures is discussed. Two electron density regimes are found, which are distinguished by the population and depopulation mechanisms for the excited states in problem. When the electron impact excitation frequency for the population or depopulation is lower than the atomic impact one, the electron density of the plasma is considered as low to estimate the population and depopulation processes. Some remarkable characteristics of population and depopulation mechanisms are found for the low electron density atmospheric plasma, where thermal relaxation by atomic collisions becomes the predominant process within the group of close-energy states in the ionizing plasma of atmospheric pressure, and the excitation temperature is almost the same as the gas temperature. In addition to the collisional relaxation by argon atoms, electron impact excitation from the ground state is also an essential population mechanism. The ratios of population density of the levels pairs, between which exists a large energy gap, include information on the electron collisional kinetics. For high electron density, the effect of atomic collisional relaxation becomes weak. For this case, the excitation mechanism is explained as electron impact ladderlike excitation similar to low-pressure ionizing plasma, since the electron collision becomes the dominant process for the population and depopulation kinetics.

  17. Tailoring dye-sensitized upconversion nanoparticle excitation bands towards excitation wavelength selective imaging

    NASA Astrophysics Data System (ADS)

    Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; Zhang, Yuanwei; Li, Zhanjun; Chen, Teresa; Liu, Yi; Duan, Chunying; Shen, Jie; Punjabi, Amol; Han, Gang

    2015-11-01

    One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs.One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs. Electronic supplementary information (ESI) available: Experimental details for the synthesis, TEM, FTIR spectra, absorption and PL spectra. See DOI: 10.1039/c5nr05437k

  18. Patterns of conductivity in excitable automata with updatable intervals of excitations.

    PubMed

    Adamatzky, Andrew

    2012-11-01

    We define a cellular automaton where a resting cell excites if number of its excited neighbors belong to some specified interval and boundaries of the interval change depending on ratio of excited and refractory neighbors in the cell's neighborhood. We calculate excitability of a cell as a number of possible neighborhood configurations that excite the resting cell. We call cells with maximal values of excitability conductive. In exhaustive search of functions of excitation interval updates we select functions which lead to formation of connected configurations of conductive cells. The functions discovered are used to design conductive, wirelike, pathways in initially nonconductive arrays of cells. We demonstrate that by positioning seeds of growing conductive pathways it is possible to implement a wide range of routing operations, including reflection of wires, stopping wires, formation of conductive bridges, and generation of new wires in the result of collision. The findings presented may be applied in designing conductive circuits in excitable nonlinear media, reaction-diffusion chemical systems, neural tissue, and assemblies of conductive polymers. PMID:23214841

  19. Resonance enhanced electron impact excitation for P-like Cu XV

    NASA Astrophysics Data System (ADS)

    Li, Shuang; Yan, Jun; Li, Chuan-Ying; Huang, Min; Chen, Chong-Yang

    2015-11-01

    Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated resonance approaches, we report resonance enhanced electron impact excitation data (specifically, effective collision strengths) among the lowest 41 levels from the n = 3 configurations of Cu XV. The results show that the latter approach can obtain resonance contributions reasonably well for most excitations of Cu XV, though a comparison between the two approaches shows that the close-coupling effects are truly significant for rather weak excitations, especially for two-electron excitations from the 3s3p4 to 3s23p23d configuration. Resonance contributions are significant (more than two orders of magnitude) for many excitations and dramatically influence the line intensity ratios associated with density diagnostics. Project supported by the National Natural Science Foundation of China (Grant Nos. 11076009 and 11374062), the Chinese Association of Atomic and Molecular Data, the Chinese National Fusion Project for ITER (Grant No. 2015GB117000), and the Leading Academic Discipline Project of Shanghai, China (Grant No. B107).

  20. How a Trip to the Freezer Can Help Children Learn Science

    ERIC Educational Resources Information Center

    Keogh, Brenda; Naylor, Stuart

    2011-01-01

    There are lots of exciting ways for children to learn science. Going on a journey is one of them. However, when going to distant places is not possible, a virtual journey may be the next best option. Ricky, one of the authors' puppets, helps children to make virtual journeys, and this can create an exciting context for them to raise questions and